Temperature Converter

Convert between Celsius, Fahrenheit and Kelvin. Free, and the conversion runs on your own device.

How it works

Temperature is the one measurement here that a single factor cannot carry. A length of zero is zero in every unit. A temperature of zero is not, because the three scales start in different places. Each unit carries a pair of formulas instead.

The kelvin is the base. Every value goes into kelvin first, and then out of kelvin into the unit you asked for.

K = C + 273.15 and C = K - 273.15

K = (F - 32) * 5 / 9 + 273.15 and F = (K - 273.15) * 9 / 5 + 32

  1. Type the reading into the first field.
  2. Choose the scale you have, and the scale you want.
  3. Read the converted temperature in the second field.
  4. Use the swap button to turn the pair around.

Both fields accept a number. Type into the second field and the first one follows, so a conversion runs in either direction.

Three units are available: Kelvin, Celsius and Fahrenheit. There is no Rankine and no Reaumur. Put the formulas together and Celsius to Fahrenheit becomes multiply by 9, divide by 5, add 32.

A result is rounded to 12 significant digits. The whole conversion runs in your browser.

Worked examples

A body temperature of 37 degrees Celsius in Fahrenheit

37 degrees Celsius is 98.6 degrees Fahrenheit, and 310.15 kelvin.

Read it the other way and 98.6 degrees Fahrenheit is 37 degrees Celsius. A fever of 38 degrees Celsius is 100.4 degrees Fahrenheit, and 39 is 102.2.

An oven set to 350 degrees Fahrenheit

350 degrees Fahrenheit is 176.666666667 degrees Celsius, which is why a recipe rounds it to 175 or 180. Further up the dial, 425 degrees Fahrenheit is 218.333333333 degrees Celsius.

From the metric side the numbers land clean. 160 degrees Celsius is 320 degrees Fahrenheit, 180 is 356, 200 is 392, and 220 is 428.

Frequently asked questions

What is 100 degrees Celsius in Fahrenheit?

212 degrees Fahrenheit, the boiling point of water at sea level. Water freezes at 0 degrees Celsius, which is 32 degrees Fahrenheit. Between them, 10 degrees Celsius is 50, 20 is 68, 25 is 77, 30 is 86, and 40 is 104.

What is 72 degrees Fahrenheit in Celsius?

22.2222222222 degrees Celsius. The digits repeat because the conversion divides by 9. Nearby, 60 degrees Fahrenheit is 15.5555555556 Celsius, 90 is 32.2222222222, and 100 is 37.7777777778.

At what temperature are Celsius and Fahrenheit the same?

At minus 40. Enter minus 40 Celsius and the result is minus 40 Fahrenheit. Enter minus 40 Fahrenheit and the result is minus 40 Celsius. The two scales cross once, and only there.

Can I convert a temperature difference?

Not directly. The converter converts a reading, and a reading carries the offset. Enter 1 degree Celsius and the result is 33.8 degrees Fahrenheit, not 1.8. A difference of one degree Celsius is a difference of 1.8 degrees Fahrenheit. Multiply a difference by 9 and divide by 5 in the Calculator.

What is absolute zero?

0 kelvin, which is minus 273.15 degrees Celsius and minus 459.67 degrees Fahrenheit. The converter does not stop there. Minus 273.16 degrees Celsius reports minus 0.01 kelvin, which is a number rather than a temperature.

Is anything I type stored?

No. There is no account, and nothing you type reaches a server. The application is stored in the browser after your first visit, so the converter works with no internet connection. No result is written down.

Good to know

A step of one kelvin and a step of one degree Celsius are the same size. Only the starting point differs, by exactly 273.15. That is why the Celsius formulas add and subtract, and never multiply. A degree Fahrenheit is the smaller step, five ninths of the other two.

Common temperature conversions:

  • 0 degrees Celsius = 32 degrees Fahrenheit
  • 20 degrees Celsius = 68 degrees Fahrenheit
  • 37 degrees Celsius = 98.6 degrees Fahrenheit
  • 100 degrees Celsius = 212 degrees Fahrenheit
  • 32 degrees Fahrenheit = 0 degrees Celsius
  • 98.6 degrees Fahrenheit = 37 degrees Celsius
  • 0 kelvin = minus 273.15 degrees Celsius

Rounding hides a small effect. Converting 300 kelvin to Celsius produces a number just above 26.85, because 273.15 cannot be held exactly in binary. The rounding at 12 significant digits shows 26.85.

The nine converters share one workspace, so a value typed here is still in the field when you open another measurement. For one that converts by a plain factor, use the Length Converter.