Convert between Celsius (°C), Fahrenheit (°F) and Kelvin (K) with the exact offset formulas.
How temperature conversion works
Temperature is unlike every other category: the scales have different zero points, so converting needs a formula with an offset rather than a plain multiplication. Celsius and Kelvin share the same step size (K = °C + 273.15), while Fahrenheit degrees are smaller — °F = °C × 9/5 + 32.
| Conversion | Formula |
| °C to °F | °F = °C × 9/5 + 32 |
| °F to °C | °C = (°F − 32) × 5/9 |
| °C to K | K = °C + 273.15 |
| K to °C | °C = K − 273.15 |
| °F to K | K = (°F − 32) × 5/9 + 273.15 |
| K to °F | °F = (K − 273.15) × 9/5 + 32 |
All temperature conversions
Every temperature pair has its own quick-reference page with a conversion table:
Back to the full unit converter for all seven categories.
Common mistakes to avoid
- Mixing up ounces. The Weight category uses the ounce (oz), a unit of mass (28.3495 g). The Volume category uses the US fluid ounce (fl oz), a unit of capacity (29.5735 mL). One fluid ounce of water weighs about 1.04 oz, not exactly 1 oz, so always confirm which category you are in before converting.
- Confusing bits and bytes. File sizes are measured in bytes, network speeds in bits. In Data storage, 1 byte equals 8 bits, so a 100 Mbit per second connection transfers at most 12.5 megabytes per second.
- Assuming imperial gallons. Every volume unit here is US customary: 1 US gallon is 3.785 liters. A UK imperial gallon is 4.546 liters, roughly 20 percent larger, so results will not match UK fuel economy figures.
A quick accuracy check
Want to sanity-check any converter? Convert -40 from Celsius to Fahrenheit: the result must be exactly -40, the only temperature where the two scales meet. Then convert 0 Kelvin to Celsius: you should get -273.15, absolute zero. A converter that handles both edge cases correctly has sound temperature formulas, and this one does.
Frequently asked questions
What is the formula for Celsius to Fahrenheit?
Multiply by 9/5 and add 32: °F = °C × 9/5 + 32. Going back: °C = (°F − 32) × 5/9. Kelvin only shifts the zero point: K = °C + 273.15.
At what temperature do Celsius and Fahrenheit meet?
−40 °C equals −40 °F — the only point where the two scales read the same. It makes a good sanity check for any temperature converter.