Celsius, Fahrenheit and Kelvin
Celsius puts the freezing point of water at 0 and its boiling point at 100. Fahrenheit, still used in the United States, puts them at 32 and 212, so one degree Fahrenheit is 5/9 of a degree Celsius. Kelvin uses the same step size as Celsius but starts at absolute zero, the lowest possible temperature, so it has no negative values.
Temperature conversion formulas
Reference temperatures
| What | °C | °F | K |
|---|---|---|---|
| Absolute zero | -273.15 | -459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| A cold winter day | -10 | 14 | 263.15 |
| Room temperature | 20 | 68 | 293.15 |
| Normal body temperature | 37 | 98.6 | 310.15 |
| A hot summer day | 35 | 95 | 308.15 |
| Water boils at sea level | 100 | 212 | 373.15 |
| Oven for baking | 180 | 356 | 453.15 |
Celsius to Fahrenheit chart
| Degrees Celsius (°C) | Degrees Fahrenheit (°F) |
|---|---|
| -40 | -40 |
| -30 | -22 |
| -20 | -4 |
| -10 | 14 |
| -5 | 23 |
| 0 | 32 |
| 5 | 41 |
| 10 | 50 |
| 15 | 59 |
| 20 | 68 |
| 25 | 77 |
| 30 | 86 |
| 35 | 95 |
| 37 | 98.6 |
| 40 | 104 |
| 50 | 122 |
| 100 | 212 |
How to use it
- 1Pick the unit you have on the left and the unit you want on the right.
- 2Type a value on either side. The other side updates as you type, and the swap button turns the conversion around.
- 3Read the result and the factor below it, or tap any unit in the list to convert into it. Copy the result or a link to share it.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (or 1.8) and add 32. For 20 °C that is 20 × 1.8 + 32 = 68 °F. For a rough estimate, double the Celsius value and add 30.
At what temperature are Celsius and Fahrenheit the same?
At −40. That is the only point where both scales show the same number.
Why does Kelvin have no degree sign?
Kelvin is an absolute scale that starts at absolute zero, and since 1967 its unit is simply called the kelvin (K), not degree Kelvin.
Can a temperature be below absolute zero?
No. Absolute zero is −273.15 °C, −459.67 °F or 0 K. The converter shows an error for anything lower.