> ## 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. # Unit Converter > Convert between units of length, mass/weight, temperature, volume, area, speed, data storage, and pressure. Pick a category, choose the units, and get an instant result — or switch on 'Show all units' to see every unit in that category at once. [Try Unit Converter in your browser →](https://iotools.cloud/tool/unit-converter/) ## OpenAPI ````yaml https://api.iotools.cloud/v1/openapi post /v1/tool/unit-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/unit-converter: post: tags: - Converters summary: Unit Converter description: >- Convert between units of length, mass/weight, temperature, volume, area, speed, data storage, and pressure. Pick a category, choose the units, and get an instant result — or switch on 'Show all units' to see every unit in that category at once. [Try Unit Converter in your browser →](https://iotools.cloud/tool/unit-converter/) operationId: run_unit_converter requestBody: required: false content: application/json: schema: type: object properties: category: enum: - length - mass - temperature - volume - area - speed - data - pressure description: Category value: type: number description: Amount lengthFrom: enum: - meter - kilometer - centimeter - millimeter - micrometer - nanometer - picometer - femtometer - decimeter - decameter - hectometer - mile - yard - foot - inch - nautical_mile - light_year - astronomical_unit - parsec - angstrom - fathom - chain - rod - league - furlong - mile_scandinavian - league_nautical - hand - cubit - pica - point - mil description: Convert from lengthTo: enum: - meter - kilometer - centimeter - millimeter - micrometer - nanometer - picometer - femtometer - decimeter - decameter - hectometer - mile - yard - foot - inch - nautical_mile - light_year - astronomical_unit - parsec - angstrom - fathom - chain - rod - league - furlong - mile_scandinavian - league_nautical - hand - cubit - pica - point - mil description: Convert to massFrom: enum: - kilogram - gram - milligram - microgram - tonne - pound - ounce - stone - ton - metric_ton - carat - atomic_mass_unit - long_ton - short_hundredweight - long_hundredweight - pennyweight - grain description: Convert from massTo: enum: - kilogram - gram - milligram - microgram - tonne - pound - ounce - stone - ton - metric_ton - carat - atomic_mass_unit - long_ton - short_hundredweight - long_hundredweight - pennyweight - grain description: Convert to temperatureFrom: enum: - C - F - K - R - De - 'N' - Re - Ro - P description: Convert from temperatureTo: enum: - C - F - K - R - De - 'N' - Re - Ro - P description: Convert to volumeFrom: enum: - milliliter - liter - cubic_centimeter - cubic_meter - us_teaspoon - us_tablespoon - us_fluid_ounce - us_cup - us_pint - us_quart - us_gallon - imp_fluid_ounce - imp_pint - imp_gallon - cubic_inch - cubic_foot description: Convert from volumeTo: enum: - milliliter - liter - cubic_centimeter - cubic_meter - us_teaspoon - us_tablespoon - us_fluid_ounce - us_cup - us_pint - us_quart - us_gallon - imp_fluid_ounce - imp_pint - imp_gallon - cubic_inch - cubic_foot description: Convert to areaFrom: enum: - square_meter - square_kilometer - square_centimeter - square_millimeter - square_decimeter - square_dekameter - square_hectometer - hectare - acre - square_foot - square_yard - square_mile - square_inch - square_micrometer - square_nanometer description: Convert from areaTo: enum: - square_meter - square_kilometer - square_centimeter - square_millimeter - square_decimeter - square_dekameter - square_hectometer - hectare - acre - square_foot - square_yard - square_mile - square_inch - square_micrometer - square_nanometer description: Convert to speedFrom: enum: - meter_per_second - kilometer_per_hour - mile_per_hour - foot_per_second - knot - kilometer_per_minute - centimeter_per_second - millimeter_per_second - mile_per_minute - inch_per_second - micrometer_per_second - nanometer_per_second description: Convert from speedTo: enum: - meter_per_second - kilometer_per_hour - mile_per_hour - foot_per_second - knot - kilometer_per_minute - centimeter_per_second - millimeter_per_second - mile_per_minute - inch_per_second - micrometer_per_second - nanometer_per_second description: Convert to dataFrom: enum: - bit - nibble - byte - kb - mb - gb - tb - pb - eb - kib - mib - gib - tib - pib - eib description: Convert from dataTo: enum: - bit - nibble - byte - kb - mb - gb - tb - pb - eb - kib - mib - gib - tib - pib - eib description: Convert to pressureFrom: enum: - pascal - kilopascal - megapascal - bar - millibar - atmosphere - tech_atmosphere - psi - ksi - torr - inhg - cmh2o description: Convert from pressureTo: enum: - pascal - kilopascal - megapascal - bar - millibar - atmosphere - tech_atmosphere - psi - ksi - torr - inhg - cmh2o description: Convert to showAll: type: boolean description: Show all units precision: enum: - '0' - '2' - '4' - '6' - '8' - '10' description: Decimal precision required: [] examples: 1_meter_to_feet_length: summary: 1 meter to feet (Length) value: category: length value: '1' lengthFrom: meter lengthTo: foot precision: '4' 150_lb_to_kilograms_mass_weight: summary: 150 lb to kilograms (Mass / Weight) value: category: mass value: '150' massFrom: pound massTo: kilogram precision: '2' 100_c_to_fahrenheit_temperature: summary: 100 °C to Fahrenheit (Temperature) value: category: temperature value: '100' temperatureFrom: C temperatureTo: F precision: '2' 5_us_gallons_to_liters_volume: summary: 5 US gallons to liters (Volume) value: category: volume value: '5' volumeFrom: us_gallon volumeTo: liter precision: '2' 1_acre_to_square_meters_area: summary: 1 acre to square meters (Area) value: category: area value: '1' areaFrom: acre areaTo: square_meter precision: '2' 60_mph_to_km_h_speed: summary: 60 mph to km/h (Speed) value: category: speed value: '60' speedFrom: mile_per_hour speedTo: kilometer_per_hour precision: '2' 1_gb_to_gib_data_storage: summary: 1 GB to GiB (Data Storage) value: category: data value: '1' dataFrom: gb dataTo: gib precision: '4' 1_atm_to_psi_pressure: summary: 1 atm to PSI (Pressure) value: category: pressure value: '1' pressureFrom: atmosphere pressureTo: psi precision: '2' 1_meter_to_every_length_unit: summary: 1 meter to every length unit value: category: length value: '1' lengthFrom: meter showAll: 'true' precision: '4' responses: '200': description: Tool output content: application/json: examples: 1_meter_to_feet_length: summary: 1 meter to feet (Length) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 3.2808 Foot (ft) table: [] credits_used: 3 credits_remaining: null 150_lb_to_kilograms_mass_weight: summary: 150 lb to kilograms (Mass / Weight) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 68.04 Kilogram (kg) table: [] credits_used: 3 credits_remaining: null 100_c_to_fahrenheit_temperature: summary: 100 °C to Fahrenheit (Temperature) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 212 Fahrenheit (°F) table: [] credits_used: 3 credits_remaining: null 5_us_gallons_to_liters_volume: summary: 5 US gallons to liters (Volume) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 18.93 Liter (L) table: [] credits_used: 3 credits_remaining: null 1_acre_to_square_meters_area: summary: 1 acre to square meters (Area) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 4046.86 Square Meter (m²) table: [] credits_used: 3 credits_remaining: null 60_mph_to_km_h_speed: summary: 60 mph to km/h (Speed) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 96.56 Kilometer per Hour (km/h) table: [] credits_used: 3 credits_remaining: null 1_gb_to_gib_data_storage: summary: 1 GB to GiB (Data Storage) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 0.9313 Gibibyte (GiB) table: [] credits_used: 3 credits_remaining: null 1_atm_to_psi_pressure: summary: 1 atm to PSI (Pressure) value: tool: unit-converter tool_version: 1.0.1 outputs: result: 14.7 Pounds per Square Inch (psi) table: [] credits_used: 3 credits_remaining: null 1_meter_to_every_length_unit: summary: 1 meter to every length unit value: tool: unit-converter tool_version: 1.0.1 outputs: result: '' table: - unit: Meter (m) value: '1' - unit: Kilometer (km) value: '0.001' - unit: Centimeter (cm) value: '100' - unit: Millimeter (mm) value: '1000' - unit: Micrometer (μm) value: '1000000' - unit: Nanometer (nm) value: '1000000000' - unit: Picometer (pm) value: '1000000000000' - unit: Femtometer (fm) value: '999999999999999.9' - unit: Decimeter (dm) value: '10' - unit: Decameter (dam) value: '0.1' - unit: Hectometer (hm) value: '0.01' - unit: Mile (mi) value: '0.0006' - unit: Yard (yd) value: '1.0936' - unit: Foot (ft) value: '3.2808' - unit: Inch (in) value: '39.3701' - unit: Nautical Mile (nmi) value: '0.0005' - unit: Light Year (ly) value: '1.0570e-16' - unit: Astronomical Unit (AU) value: '6.6846e-12' - unit: Parsec (pc) value: '3.2408e-17' - unit: Angstrom (Å) value: '10000000000' - unit: Fathom (fth) value: '0.5468' - unit: Chain (ch) value: '0.0497' - unit: Rod (rd) value: '0.1988' - unit: League (leag) value: '0.0002' - unit: Furlong (fur) value: '0.005' - unit: Scandinavian Mile (mil) value: '0.0001' - unit: Nautical League (ln) value: '0.0002' - unit: Hand (h) value: '9.8425' - unit: Cubit (cbt) value: '2.1872' - unit: Pica (pi) value: '236.2205' - unit: Point (pt) value: '2834.6457' - unit: Mil (mil) value: '39370.0787' credits_used: 3 credits_remaining: null schema: type: object required: - tool - tool_version - outputs - credits_used - credits_remaining properties: outputs: type: object properties: result: type: string description: Result table: type: array description: Converted to every unit items: type: object properties: unit: type: string description: Unit value: type: string description: Value x-iotools-columns: - unit - value 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_… ````