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Temperature converter

Convert °C, °F, Kelvin, and Rankine without an offset mistake.

This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.

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What this tool does

Temperature is affine, not a single multiply. Celsius and Kelvin share a degree size; Fahrenheit and Rankine share another. ConvertPass goes through kelvin and refuses a result below 0 K.

How to use it

  1. Enter the temperature.
  2. Pick the source scale and the destination scale.
  3. Convert and copy the JSON.

Supported input

  • A number and two temperature scales

Output

  • JSON with the converted temperature plus every other scale in the family

Privacy

This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.

ConvertPass does not include your input in analytics, URLs, or error reports. Encoding: Decimal numbers / SI kelvin. Limit: A single temperature (4.0 KB).

Limitations

  • This is thermodynamic temperature, not wind chill, heat index, or colour temperature in kelvin for lighting.
  • ITS-90 versus IPTS-68 differences are not modelled. Use a metrology lab for calibration certificates.
  • Rankine and Kelvin cannot be negative. Celsius and Fahrenheit may be negative down to absolute zero.

Example

Input
0 °C → °F
Output
{
  "result": 32,
  "formatted": "0 °C = 32 °F"
}

Boiling water at 100 °C is 373.15 K at standard pressure, which this tool does not check.

Troubleshooting

The tool refused −300 °C
That is below absolute zero. Check the sign or the scale.

FAQ

Is 0 K the same as −273.15 °C?

Yes in this converter. That is the SI definition used here.

Why include Rankine?

Some US engineering texts still use it. It is Fahrenheit-sized degrees starting at absolute zero.

Does this convert oven gas marks?

No. Gas marks are manufacturer conventions, not a scale ConvertPass will guess.

Is this a weather forecast?

No. It converts a number you already have. It does not know the temperature outside.

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Related formats

Last reviewed 16 August 2026. Report a problem. Reports do not include your input.