Temperature Converter

How to use the temperature converter

1. Type the temperature you want to convert. Negative numbers such as -40 are fine.
2. Choose the scale you are converting from and the scale you want to convert to.
3. The answer appears as you type, along with the same temperature on every other scale. Use Swap units to reverse the conversion.

Temperature formulas

• Celsius to Fahrenheit: °F = °C × 9/5 + 32
• Fahrenheit to Celsius: °C = (°F − 32) × 5/9
• Celsius to Kelvin: K = °C + 273.15
• Fahrenheit to Kelvin: K = (°F + 459.67) × 5/9
• Rankine: °R = K × 9/5, which equals °F + 459.67
• Réaumur: °Ré = °C × 4/5

Handy reference points

• Absolute zero: -273.15 °C, -459.67 °F, 0 K
• Water freezes: 0 °C, 32 °F, 273.15 K
• Room temperature: about 20 to 22 °C, or 68 to 72 °F
• Normal body temperature: about 37 °C, or 98.6 °F
• Water boils at sea level: 100 °C, 212 °F, 373.15 K
• -40 is the same on the Celsius and Fahrenheit scales.

Good to know

• Absolute zero is the limit. Nothing can be colder than 0 K, so the converter shows a message if a value is below it.
• Kelvin has no degree sign. It is written as K, not °K.
• Temperature differences convert differently. A change of 10 °C is a change of 18 °F, not 50 °F. This tool converts single temperatures, not differences.
• Rounding: results are shown to about 10 significant digits, and tiny floating-point errors are removed so that 32 °F shows as exactly 0 °C.
• Rankine and Réaumur are older scales, mostly used in engineering and history. They are included for completeness.

Is it private?

Yes. Every conversion happens in your web browser. The numbers you enter are never uploaded or stored, and this tool needs no outside libraries.