Temperature Converter

This temperature converter switches between Celsius, Fahrenheit, Kelvin, and Rankine. Type a temperature in one scale and read it in the other three straight away.

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How to use the Temperature Converter

  1. Type the Value you want to convert.
  2. Pick the unit it is in under From, and the unit you want under To. The swap button flips them.
  3. The answer updates as you type. The table below it shows the same value in every other unit, each with its own copy button.

How it works

Temperature scales have different zero points, so they need formulas instead of a single factor:

°F = °C × 9/5 + 32
°C = (°F − 32) × 5/9
K  = °C + 273.15
°R = °F + 459.67 = K × 9/5

Internally every value goes through kelvin, the SI unit, and back out to the scale you picked.

Examples

  • 100 °C = 212 °F, the boiling point of water at sea level.
  • 98.6 °F = 37 °C, a typical body temperature.
  • 0 K = −273.15 °C = −459.67 °F (absolute zero).
  • −40 °C = −40 °F, the one point where both scales agree.

Celsius to Fahrenheit conversion table

Celsius (°C)Fahrenheit (°F)
-40 °C-40 °F
-20 °C-4 °F
-10 °C14 °F
0 °C32 °F
10 °C50 °F
20 °C68 °F
25 °C77 °F
30 °C86 °F
37 °C98.6 °F
100 °C212 °F

Room temperature is about 20 to 22 °C (68 to 72 °F). Water freezes at 0 °C (32 °F).

Fahrenheit to Celsius conversion table

Fahrenheit (°F)Celsius (°C)
0 °F-17.777778 °C
32 °F0 °C
50 °F10 °C
68 °F20 °C
72 °F22.222222 °C
98.6 °F37 °C
100 °F37.777778 °C
212 °F100 °C
350 °F176.666667 °C
400 °F204.444444 °C

Oven temperatures in recipes: 350 °F is about 177 °C, and 400 °F is about 204 °C.

Why there are four scales

Celsius puts 0 at the freezing point of water and 100 at its boiling point. Fahrenheit, still used in the United States, puts those points at 32 and 212. Kelvin starts at absolute zero, the coldest possible temperature, and uses Celsius-sized steps; scientists use it because it never goes negative. Rankine does the same with Fahrenheit-sized steps and shows up in some US engineering work.

A temperature difference converts differently from a temperature. A change of 10 °C is a change of 18 °F, not 50 °F.

Limitations

  • Values below absolute zero (−273.15 °C, −459.67 °F, 0 K) give an error.
  • This converts temperatures, not temperature differences. For a difference, multiply Celsius by 1.8 to get Fahrenheit.

Frequently asked questions

How do I convert Celsius to Fahrenheit?

Multiply by 9/5 (or 1.8) and add 32. For example, 25 °C × 1.8 + 32 = 77 °F.

How do I convert Fahrenheit to Celsius?

Subtract 32, then multiply by 5/9. For example, (68 °F − 32) × 5/9 = 20 °C.

At what temperature are Celsius and Fahrenheit equal?

At −40. −40 °C and −40 °F are the same temperature.

Why is there no degree sign on kelvin?

Kelvin is an absolute scale and an SI base unit, so it is written as K without the degree sign, for example 300 K.

Often used together with the Temperature Converter.