> ## 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. # Decibel (dB) Converter > Convert decibel levels to and from their linear quantities and ratios for Sound Pressure Level (dB SPL), Voltage (dBV / dBu) and Power (dBm / dBW). Enter a value in any unit and read the equivalents, with the formulas and common reference levels. [Try Decibel (dB) Converter in your browser →](https://iotools.cloud/tool/decibel-converter/) ## OpenAPI ````yaml https://api.iotools.cloud/v1/openapi post /v1/tool/decibel-converter 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/decibel-converter: post: tags: - Converters summary: Decibel (dB) Converter description: >- Convert decibel levels to and from their linear quantities and ratios for Sound Pressure Level (dB SPL), Voltage (dBV / dBu) and Power (dBm / dBW). Enter a value in any unit and read the equivalents, with the formulas and common reference levels. [Try Decibel (dB) Converter in your browser →](https://iotools.cloud/tool/decibel-converter/) operationId: run_decibel_converter requestBody: required: true content: application/json: schema: type: object properties: refType: enum: - spl - voltage - power description: Reference value: type: number description: Value unitSpl: enum: - dbspl - pa - pratio - iratio description: Unit unitVoltage: enum: - dbv - dbu - v - vratio - vpratio description: Unit unitPower: enum: - dbm - dbw - w - pratiop description: Unit required: - value examples: 85_db_spl_to_pressure_ratios: summary: 85 dB SPL to pressure & ratios value: refType: spl value: '85' unitSpl: dbspl 4_dbu_to_volts_dbv: summary: +4 dBu to volts & dBV value: refType: voltage value: '4' unitVoltage: dbu 20_dbm_to_watts_dbw: summary: 20 dBm to watts & dBW value: refType: power value: '20' unitPower: dbm 0_02_pa_to_db_spl: summary: 0.02 Pa to dB SPL value: refType: spl value: '0.02' unitSpl: pa responses: '200': description: Tool output content: application/json: examples: 85_db_spl_to_pressure_ratios: summary: 85 dB SPL to pressure & ratios value: tool: decibel-converter tool_version: 1.0.1 outputs: results: - quantity: dB SPL value: 85 dB SPL - quantity: Sound Pressure value: 0.3557 Pa - quantity: Pressure Ratio (p / p₀) value: '17782.7941' - quantity: Intensity Ratio (I / I₀) value: '3.1623e+8' reference: - source: Threshold of hearing level: 0 dB - source: Rustling leaves level: 10 dB - source: Whisper at 1 m level: 30 dB - source: Quiet library / office level: 40 dB - source: Normal conversation level: 60 dB - source: Busy traffic level: 75 dB - source: Vacuum cleaner level: 80 dB - source: Heavy traffic / lawn mower level: 90 dB - source: Subway / motorcycle level: 100 dB - source: Live rock concert level: 110 dB - source: Threshold of pain level: 130 dB - source: Jet engine at 30 m level: 140 dB - source: Firearm muzzle blast level: 160 dB formula: |- Sound Pressure Level (reference p₀ = 20 µPa) dB SPL = 20 · log₁₀(p / p₀) p = p₀ · 10^(dB SPL / 20) Pressure Ratio = p / p₀ Intensity Ratio (I / I₀) = (p / p₀)² credits_used: 3 credits_remaining: null 4_dbu_to_volts_dbv: summary: +4 dBu to volts & dBV value: tool: decibel-converter tool_version: 1.0.1 outputs: results: - quantity: dBV value: 1.7815 dBV - quantity: dBu value: 4 dBu - quantity: Voltage value: 1.2277 V - quantity: Amplitude Ratio (V / V₀) value: '1.2277' - quantity: Power Ratio (P / P₀) value: '1.5071' formula: |- Voltage (dBV reference = 1 V, dBu reference ≈ 0.7746 V) dBV = 20 · log₁₀(V / 1 V) dBu = 20 · log₁₀(V / 0.7746 V) V = V_ref · 10^(dB / 20) Amplitude Ratio = V / V_ref Power Ratio = (V / V_ref)² reference: - source: Pro audio nominal (+4 dBu) level: +4 dBu ≈ +1.78 dBV - source: Consumer audio nominal (-10 dBV) level: '-10 dBV ≈ -7.78 dBu' - source: Microphone (dynamic, typical) level: '-60 to -40 dBu' - source: Line level (line-out, pro) level: 0 dBu (0.775 V) - source: Line level (line-out, consumer) level: '-10 dBV (0.316 V)' - source: Headphone amp output level: 0 to +6 dBu credits_used: 3 credits_remaining: null 20_dbm_to_watts_dbw: summary: 20 dBm to watts & dBW value: tool: decibel-converter tool_version: 1.0.1 outputs: results: - quantity: dBm value: 20 dBm - quantity: dBW value: '-10 dBW' - quantity: Power value: 0.1000 W - quantity: Power Ratio (P / P₀) value: '0.1000' reference: - source: Bluetooth (Class 2) level: +4 dBm (2.5 mW) - source: Wi-Fi router (typical) level: +20 dBm (100 mW) - source: Cellular handset (max) level: +33 dBm (2 W) - source: FM radio broadcast (small) level: +47 dBm (50 W) - source: Microwave oven level: +60 dBm (1 kW) - source: AM radio broadcast level: +90 dBm (1 MW) - source: Receiver noise floor (typical) level: '-100 dBm' - source: GPS signal at Earth level: '-130 dBm' formula: |- Power (dBm reference = 1 mW, dBW reference = 1 W) dBm = 10 · log₁₀(P / 1 mW) dBW = 10 · log₁₀(P / 1 W) P = P_ref · 10^(dB / 10) Power Ratio = P / P_ref dBm = dBW + 30 credits_used: 3 credits_remaining: null 0_02_pa_to_db_spl: summary: 0.02 Pa to dB SPL value: tool: decibel-converter tool_version: 1.0.1 outputs: results: - quantity: dB SPL value: 60 dB SPL - quantity: Sound Pressure value: 0.02000 Pa - quantity: Pressure Ratio (p / p₀) value: '1000' - quantity: Intensity Ratio (I / I₀) value: '1000000' formula: |- Sound Pressure Level (reference p₀ = 20 µPa) dB SPL = 20 · log₁₀(p / p₀) p = p₀ · 10^(dB SPL / 20) Pressure Ratio = p / p₀ Intensity Ratio (I / I₀) = (p / p₀)² reference: - source: Threshold of hearing level: 0 dB - source: Rustling leaves level: 10 dB - source: Whisper at 1 m level: 30 dB - source: Quiet library / office level: 40 dB - source: Normal conversation level: 60 dB - source: Busy traffic level: 75 dB - source: Vacuum cleaner level: 80 dB - source: Heavy traffic / lawn mower level: 90 dB - source: Subway / motorcycle level: 100 dB - source: Live rock concert level: 110 dB - source: Threshold of pain level: 130 dB - source: Jet engine at 30 m level: 140 dB - source: Firearm muzzle blast level: 160 dB credits_used: 3 credits_remaining: null schema: type: object required: - tool - tool_version - outputs - credits_used - credits_remaining properties: outputs: type: object properties: results: type: array items: type: object properties: quantity: type: string description: Quantity value: type: string description: Value x-iotools-columns: - quantity - value formula: type: string description: Formulas reference: type: array items: type: object properties: source: type: string description: Source level: type: string description: Level x-iotools-columns: - source - level 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 ''.' 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_… ````