°C · °F · K
Temperature converter
Fahrenheit equals Celsius × 9/5 + 32, so 0 °C is exactly 32 °F and 100 °C is exactly 212 °F. Enter a temperature, pick a scale and read it in all three scales at once.
- 0 °C = 32 °F
- 0 °F = -17.77778 °C
The result and the table below it update as you type. Only the printed figure is rounded, to six significant digits, so a rounded value is never carried into the next conversion.
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At a glance
- Price
- No charge
- Account
- None needed
- Upload
- Not applicable — you type a value, nothing is sent anywhere
- Scales
- Celsius (°C), Fahrenheit (°F) and Kelvin (K)
- Precision
- Exact formulas, printed to six significant digits
- Works on
- Any modern browser
Common temperature conversions
These tables are computed from the same formulas as the converter. Read each one left to right: the first column is the value you start with and the second is its equivalent.
| °C | °F |
|---|---|
| -40 | -40 |
| 0 | 32 |
| 20 | 68 |
| 37 | 98.6 |
| 100 | 212 |
| °F | °C |
|---|---|
| -40 | -40 |
| 0 | -17.7778 |
| 20 | -6.66667 |
| 37 | 2.77778 |
| 100 | 37.7778 |
| °C | K |
|---|---|
| -40 | 233.15 |
| 0 | 273.15 |
| 20 | 293.15 |
| 37 | 310.15 |
| 100 | 373.15 |
| K | °C |
|---|---|
| -40 | -313.15 |
| 0 | -273.15 |
| 20 | -253.15 |
| 37 | -236.15 |
| 100 | -173.15 |
How to convert a temperature
Enter the temperature
Type a number in the first field. Negative values and decimals are accepted, so 36.6 and −40 both work.
Pick the two scales
Choose the scale you have in the first menu and the scale you want in the second. The swap button reverses the two.
Read the table
The large figure is your answer. The table lists the same temperature on every other scale, so you can copy the one you need without converting again.
How temperature conversion works
This page has three scales. Kelvin (K, written without a degree sign) starts at absolute zero, so 0 K is −273.15 °C. A Celsius degree and a kelvin are the same size, so 0 °C is 273.15 K. At standard atmospheric pressure, water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F). There are 180 Fahrenheit degrees between those two points and 100 Celsius degrees, so one Celsius degree is 1.8 Fahrenheit degrees. Absolute zero is −459.67 °F.
Scales with different zero points have no single multiplier. The converter moves the value to kelvin and then to the target scale. Celsius to Fahrenheit is value × 9/5 + 32, Fahrenheit to Celsius is (value − 32) × 5/9, and Celsius to Kelvin is value + 273.15. The scales meet at −40, where −40 °C and −40 °F are the same temperature. The main trap is a temperature difference: a rise of 10 °C is a rise of 18 °F, because the +32 applies only to a reading, not to a change.
Temperature conversion questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (1.8) and add 32. So 20 °C is 68 °F, 100 °C is 212 °F and 37 °C is 98.6 °F, a commonly quoted normal body temperature.
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit value, then multiply by 5/9. So 212 °F is 100 °C, 32 °F is 0 °C and 72 °F is 22.2222 °C.
Is a change of 10 °C the same as a change of 10 °F?
No. A change of 10 °C is a change of 18 °F, because one Celsius degree is 1.8 Fahrenheit degrees. The +32 offset applies only to a temperature reading, so when you convert a difference, multiply by 1.8 and do not add 32. A change of 10 K is the same size as a change of 10 °C.
Do my numbers leave my device?
No. The formulas are part of the page and the arithmetic runs in your browser, so nothing you type is sent anywhere. With the page already loaded, the converter also works offline.
How precise are the results?
Results are computed in double precision from exact formulas and printed to six significant digits; the unit table shows twelve. Values below 1e-6 or at 1e15 and above switch to exponent form so they stay readable.