Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin instantly, with the exact formula shown for every conversion.
Reference temperatures
| What | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Absolute zero | -273.15 | -459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| Room temperature | 20 | 68 | 293.15 |
| Body temperature | 37 | 98.6 | 310.15 |
| Water boils | 100 | 212 | 373.15 |
| Moderate oven | 180 | 356 | 453.15 |
| Hot oven | 220 | 428 | 493.15 |
The three temperature formulas
All three scales measure the same thing, just from different starting points and with different step sizes. Celsius and Kelvin share the same size of degree; Fahrenheit degrees are smaller (1.8 of them fit in one Celsius degree). Here are the conversions the tool applies:
- Celsius to Fahrenheit:
(C x 9/5) + 32 - Fahrenheit to Celsius:
(F - 32) x 5/9 - Celsius to Kelvin:
C + 273.15 - Kelvin to Celsius:
K - 273.15
Everyday examples
A hot summer day at 30 C is (30 x 1.8) + 32 = 86 F. A fever of 39 C is 102.2 F. Fan-oven baking at 200 C is 392 F. When someone quotes "it is 100 out" in the US they mean 100 F, which is a sweltering 37.8 C - almost body temperature. The formula line under the result spells out the exact arithmetic each time so you can follow along or double-check it.
Why Kelvin has no minus sign
Kelvin starts at absolute zero, the point where all molecular motion stops, so it never goes negative. That is why scientists use it: 0 K is -273.15 C. If you enter a temperature that would fall below absolute zero, the tool flags it, because no real object can be that cold. For time and date maths instead of temperature, see the date calculator; for other measures, the unit converter and length converter cover the rest.
Popular conversions
- degrees Celsius to degrees Fahrenheit (°C to °F) - °F = °C x 9/5 + 32
- degrees Fahrenheit to degrees Celsius (°F to °C) - °C = (°F − 32) x 5/9