> ## Documentation Index
> Fetch the complete documentation index at: https://docs.iotools.cloud/llms.txt
> Use this file to discover all available pages before exploring further.

# Solar PV System Sizing Calculator

> Size a solar PV system from your daily energy usage, peak sun hours and panel wattage: required array capacity, number of panels, recommended inverter size, and — for off-grid systems — battery bank capacity from days of autonomy and depth of discharge. Runs entirely in your browser.

[Try Solar PV System Sizing Calculator in your browser →](https://iotools.cloud/tool/solar-pv-system-sizing-calculator/)



## OpenAPI

````yaml https://api.iotools.cloud/v1/openapi post /v1/tool/solar-pv-system-sizing-calculator
openapi: 3.1.0
info:
  title: iotools.cloud API
  version: 1.0.0
  description: >-
    Run any iotools.cloud tool over HTTP.


    Authenticate with `Authorization: Bearer iot_live_…`.


    **Only `POST /v1/tool/{slug}` costs credits.** Every GET here — the catalog,
    a tool's schema, your balance — is free. A tool call is charged its own
    weight or your plan's per-call minimum, whichever is larger;
    `x-iotools-credit-cost` on each operation is quoted at the free-tier
    minimum, and `GET /v1/tools/list` returns the exact figure for your key.
    `GET /v1/me/credits` reports what you have left, and `GET /v1/me/usage`
    reports what it went on.


    Failures are RFC 9457 problem documents — branch on `code`.
servers:
  - url: https://api.iotools.cloud
    description: Production
security:
  - bearerAuth: []
tags:
  - name: Catalog
    description: Find a tool and read its contract. Free.
  - name: Converters
    description: >-
      Convert between formats, encodings, and units — Base64, CSV and JSON,
      timestamps, and more. Fast, free, and processed right in your browser.
  - name: Formatters
    description: >-
      Format, beautify, minify, and validate code and data — JSON, HTML, CSS,
      SQL, and regex. Clean up messy input in one click, with nothing to upload.
  - name: Generators
    description: >-
      Generate exactly what you need and on demand — passwords, UUIDs, QR codes,
      hashes, random numbers, and more. Secure, instant, and free.
  - name: Calculators
    description: >-
      Crunch the numbers fast — from everyday math to specialized conversions
      and unit work. Free online calculators that run entirely in your browser.
  - name: Editors
    description: >-
      Edit and transform text, code, and images with quick, focused editors that
      run entirely in your browser — nothing to install, and no sign-up needed.
  - name: Utilities
    description: >-
      Everyday developer and web utilities — DNS and IP lookups, redirect and
      certificate checkers, and other quick diagnostics. Free and
      privacy-friendly.
  - name: Account
    description: Your key's allowance, limits and usage history.
paths:
  /v1/tool/solar-pv-system-sizing-calculator:
    post:
      tags:
        - Calculators
      summary: Solar PV System Sizing Calculator
      description: >-
        Size a solar PV system from your daily energy usage, peak sun hours and
        panel wattage: required array capacity, number of panels, recommended
        inverter size, and — for off-grid systems — battery bank capacity from
        days of autonomy and depth of discharge. Runs entirely in your browser.


        [Try Solar PV System Sizing Calculator in your browser
        →](https://iotools.cloud/tool/solar-pv-system-sizing-calculator/)
      operationId: run_solar_pv_system_sizing_calculator
      requestBody:
        required: false
        content:
          application/json:
            schema:
              type: object
              properties:
                dailyUsage:
                  type: number
                  description: Average daily energy usage (kWh/day)
                  minimum: 0.1
                  maximum: 100000
                peakSunHours:
                  type: number
                  description: Peak sun hours (h/day)
                  minimum: 0.5
                  maximum: 12
                panelWattage:
                  type: number
                  description: Solar panel wattage (W)
                  minimum: 50
                  maximum: 700
                systemEfficiency:
                  type: number
                  description: System derate factor (%)
                  minimum: 50
                  maximum: 95
                dcAcRatio:
                  type: number
                  description: DC:AC (inverter loading) ratio
                  minimum: 1
                  maximum: 1.5
                mode:
                  enum:
                    - grid-tied
                    - off-grid
                  description: System type
                autonomyDays:
                  type: number
                  description: Days of autonomy (battery reserve)
                  minimum: 0.5
                  maximum: 14
                depthOfDischarge:
                  type: number
                  description: Battery depth of discharge (%)
                  minimum: 10
                  maximum: 100
                batteryVoltage:
                  enum:
                    - '12'
                    - '24'
                    - '48'
                  description: Battery bank voltage
              required: []
            examples:
              grid_tied_30_kwh_day_400w_panels:
                summary: Grid-tied, 30 kWh/day, 400W panels
                value:
                  dailyUsage: '30'
                  peakSunHours: '4.5'
                  panelWattage: '400'
                  systemEfficiency: '77'
                  dcAcRatio: '1.2'
                  mode: grid-tied
              off_grid_cabin_15_kwh_day_3_days_autonomy:
                summary: Off-grid cabin, 15 kWh/day, 3 days autonomy
                value:
                  dailyUsage: '15'
                  peakSunHours: '5'
                  panelWattage: '350'
                  systemEfficiency: '75'
                  dcAcRatio: '1.15'
                  mode: off-grid
                  autonomyDays: '3'
                  depthOfDischarge: '50'
                  batteryVoltage: '48'
      responses:
        '200':
          description: Tool output
          content:
            application/json:
              examples:
                grid_tied_30_kwh_day_400w_panels:
                  summary: Grid-tied, 30 kWh/day, 400W panels
                  value:
                    tool: solar-pv-system-sizing-calculator
                    tool_version: 1.0.1
                    outputs:
                      systemSizeKw: 8.66 kW DC
                      panelCount: 22 panels (8.80 kW DC actual)
                      inverterSizeKw: 7.33 kW AC
                      batterySizing: N/A — grid-tied systems don't need battery storage
                      summaryTable:
                        - metric: Daily energy usage
                          value: 30.00 kWh/day
                        - metric: Peak sun hours
                          value: 4.50 h/day
                        - metric: System derate factor
                          value: 77%
                        - metric: Required array size
                          value: 8.66 kW DC
                        - metric: Panels needed
                          value: 22 × 400 W
                        - metric: Actual array size
                          value: 8.80 kW DC
                        - metric: DC:AC ratio
                          value: '1.20'
                        - metric: Inverter size
                          value: 7.33 kW AC
                      notes: >-
                        Required array size = daily usage ÷ (peak sun hours ×
                        derate) = 30.00 kWh ÷ (4.50 h × 0.77) = 8.66 kW DC.

                        Grid-tied systems don't need battery storage — excess
                        production exports to the grid, subject to your
                        utility's net-metering rules.

                        This is a rough sizing estimate for planning purposes
                        only — a licensed installer should verify against your
                        roof's actual irradiance, shading and orientation, and
                        local electrical code (e.g. NEC Article 690), before
                        purchase or installation.
                    credits_used: 3
                    credits_remaining: null
                off_grid_cabin_15_kwh_day_3_days_autonomy:
                  summary: Off-grid cabin, 15 kWh/day, 3 days autonomy
                  value:
                    tool: solar-pv-system-sizing-calculator
                    tool_version: 1.0.1
                    outputs:
                      systemSizeKw: 4.00 kW DC
                      panelCount: 12 panels (4.20 kW DC actual)
                      inverterSizeKw: 3.65 kW AC
                      batterySizing: 90.00 kWh (1,875 Ah at 48V)
                      summaryTable:
                        - metric: Daily energy usage
                          value: 15.00 kWh/day
                        - metric: Peak sun hours
                          value: 5.00 h/day
                        - metric: System derate factor
                          value: 75%
                        - metric: Required array size
                          value: 4.00 kW DC
                        - metric: Panels needed
                          value: 12 × 350 W
                        - metric: Actual array size
                          value: 4.20 kW DC
                        - metric: DC:AC ratio
                          value: '1.15'
                        - metric: Inverter size
                          value: 3.65 kW AC
                        - metric: Battery bank capacity
                          value: 90.00 kWh (1,875 Ah at 48V)
                      notes: >-
                        Required array size = daily usage ÷ (peak sun hours ×
                        derate) = 15.00 kWh ÷ (5.00 h × 0.75) = 4.00 kW DC.

                        Battery bank sized for 3.0 day(s) of autonomy at 50%
                        depth of discharge: 45.00 kWh usable ÷ 0.50 = 90.00 kWh
                        nominal capacity.

                        This is a rough sizing estimate for planning purposes
                        only — a licensed installer should verify against your
                        roof's actual irradiance, shading and orientation, and
                        local electrical code (e.g. NEC Article 690), before
                        purchase or installation.
                    credits_used: 3
                    credits_remaining: null
              schema:
                type: object
                required:
                  - tool
                  - tool_version
                  - outputs
                  - credits_used
                  - credits_remaining
                properties:
                  outputs:
                    type: object
                    properties:
                      systemSizeKw:
                        type: string
                        description: Required array size
                      panelCount:
                        type: string
                        description: Panels needed
                      inverterSizeKw:
                        type: string
                        description: Recommended inverter size
                      batterySizing:
                        type: string
                        description: Battery bank size
                      summaryTable:
                        type: array
                        description: Sizing breakdown
                        items:
                          type: object
                          properties:
                            metric:
                              type: string
                              description: Metric
                            value:
                              type: string
                              description: Value
                        x-iotools-columns:
                          - metric
                          - value
                      notes:
                        type: string
                        description: Notes
                  tool:
                    type: string
                    description: The tool's slug, echoing the {slug} in the request path.
                  tool_version:
                    type: string
                    description: Output-contract version for this tool.
                  credits_used:
                    type: integer
                    description: >-
                      Credits this call consumed, after any settlement refund. 0
                      when metering is disabled.
                  credits_remaining:
                    type:
                      - integer
                      - 'null'
                    description: >-
                      Credits left in the current monthly allowance, or null
                      when metering is disabled.
                  request_id:
                    type: string
                    description: Correlation id, also sent as x-request-id.
        '400':
          $ref: '#/components/responses/ValidationError'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '402':
          $ref: '#/components/responses/InsufficientCredits'
        '403':
          $ref: '#/components/responses/ToolNotAllowed'
        '404':
          $ref: '#/components/responses/ToolNotFound'
        '413':
          $ref: '#/components/responses/PayloadTooLarge'
        '429':
          $ref: '#/components/responses/RateLimited'
        '500':
          $ref: '#/components/responses/ToolFailed'
        '503':
          $ref: '#/components/responses/ToolDisabled'
      security:
        - bearerAuth: []
components:
  responses:
    ValidationError:
      description: Invalid request.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/validation_error
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Invalid request
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - validation_error
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
              fields:
                type:
                  - object
                  - string
                additionalProperties:
                  type: string
                description: >-
                  What failed: a map of field name → message. Absent when the
                  body itself is malformed; a single string when the failure
                  isn't tied to one field.
          example:
            type: https://iotools.cloud/docs/errors/validation_error
            title: Invalid request
            status: 400
            code: validation_error
            detail: One or more inputs are invalid — see `fields`.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
            fields:
              inputString: Required
    Unauthorized:
      description: Missing or invalid API key.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/invalid_api_key
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Invalid API key
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - invalid_api_key
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
          example:
            type: https://iotools.cloud/docs/errors/invalid_api_key
            title: Invalid API key
            status: 401
            code: invalid_api_key
            detail: 'Provide ''Authorization: Bearer <key>''.'
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
    InsufficientCredits:
      description: Monthly credit allowance exhausted.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/insufficient_credits
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Insufficient credits
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - insufficient_credits
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
              credits_used:
                type: integer
                description: Always 0 — a refused call charges nothing.
              credits_remaining:
                type: integer
                description: Credits left in the allowance — fewer than this call costs.
          example:
            type: https://iotools.cloud/docs/errors/insufficient_credits
            title: Insufficient credits
            status: 402
            code: insufficient_credits
            detail: This call costs 1 credit and 0 remain in this month's allowance.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
            credits_used: 0
            credits_remaining: 0
    ToolNotAllowed:
      description: Tool exists but has no API surface.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/tool_not_allowed
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Tool not available over the API
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - tool_not_allowed
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
          example:
            type: https://iotools.cloud/docs/errors/tool_not_allowed
            title: Tool not available over the API
            status: 403
            code: tool_not_allowed
            detail: >-
              "Background Remover" is available on iotools.cloud but has no API
              endpoint.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
    ToolNotFound:
      description: No such tool.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/tool_not_found
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Tool not found
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - tool_not_found
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
          example:
            type: https://iotools.cloud/docs/errors/tool_not_found
            title: Tool not found
            status: 404
            code: tool_not_found
            detail: No tool with that slug. See GET /v1/tools/list.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
    PayloadTooLarge:
      description: Body too large.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/payload_too_large
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Payload too large
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - payload_too_large
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
          example:
            type: https://iotools.cloud/docs/errors/payload_too_large
            title: Payload too large
            status: 413
            code: payload_too_large
            detail: Request body exceeds this tool's size limit.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
    RateLimited:
      description: Per-minute rate limit exceeded.
      headers:
        Retry-After:
          description: Seconds to wait before retrying (RFC 9110 delta-seconds).
          schema:
            type: integer
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/rate_limited
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Rate limit exceeded
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - rate_limited
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
              retry_after:
                type: integer
                description: >-
                  Seconds until the window resets — the same value as the
                  `Retry-After` header.
          example:
            type: https://iotools.cloud/docs/errors/rate_limited
            title: Rate limit exceeded
            status: 429
            code: rate_limited
            detail: Too many requests. Retry in 30s.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
            retry_after: 30
    ToolFailed:
      description: Tool failed to run.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/processing_error
                  - https://iotools.cloud/docs/errors/internal_error
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Tool failed to run
                  - Internal error
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - processing_error
                  - internal_error
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
              credits_used:
                type: integer
                description: >-
                  Always 0 on `processing_error` — a failed run is refunded,
                  floor included.
              credits_remaining:
                type: integer
                description: >-
                  Credits left after the refund. Absent when metering is
                  disabled.
          example:
            type: https://iotools.cloud/docs/errors/processing_error
            title: Tool failed to run
            status: 500
            code: processing_error
            detail: The tool failed to run. Please try again.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
            credits_used: 0
    ToolDisabled:
      description: Tool temporarily disabled.
      content:
        application/problem+json:
          schema:
            type: object
            description: >-
              RFC 9457 problem document, served as application/problem+json.
              Branch on `code`; `title` is human prose and may be reworded
              without notice. Some failures add extension members — `fields` on
              validation errors, `retry_after` on 429s,
              `credits_used`/`credits_remaining` on billing-adjacent failures —
              documented on the responses that carry them.
            required:
              - type
              - title
              - status
              - code
            properties:
              type:
                type: string
                format: uri
                description: Stable documentation URI for this failure.
                examples:
                  - https://iotools.cloud/docs/errors/tool_disabled
                  - https://iotools.cloud/docs/errors/api_unconfigured
              title:
                type: string
                description: Short human-readable summary of the failure.
                examples:
                  - Tool temporarily disabled
                  - API not configured
              status:
                type: integer
                description: HTTP status code, matching the response's own status.
              code:
                type: string
                description: >-
                  Stable machine-readable error code — branch on this, not
                  `title`.
                enum:
                  - tool_disabled
                  - api_unconfigured
              detail:
                type: string
                description: Human explanation of this occurrence.
              request_id:
                type: string
                description: Correlation id, also sent as x-request-id.
          example:
            type: https://iotools.cloud/docs/errors/tool_disabled
            title: Tool temporarily disabled
            status: 503
            code: tool_disabled
            detail: This tool is temporarily unavailable. Try again shortly.
            request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: iot_live_…

````