Three scales, one number, no mental arithmetic
Convert °C to °F, °F to °C or either to Kelvin. Built for ovens, weather forecasts and lab work where the difference actually matters.
Temperature trips people up because it is the one conversion that is not a simple multiplication. Celsius and Fahrenheit start counting from different places, so you have to shift before you scale.
The formula is °F = °C × 9/5 + 32. That +32 is why the popular 'double it and add 30' shortcut drifts badly at oven temperatures — at 200 °C it is off by 38 degrees.
What this calculator shows
- The converted temperature across Celsius, Fahrenheit and Kelvin
- Instant results for oven settings, forecasts and scientific readings
- Correct handling of negatives, where the shortcut methods fall apart
What to keep in mind
- Kelvin shares Celsius's step size but starts at absolute zero: 0 K = −273.15 °C.
- This converts temperature readings, not temperature differences — a rise of 10 °C is a rise of 18 °F, not 50 °F.
FAQs
What is 180 °C in Fahrenheit?
356 °F. Recipes almost always round it to 350 °F, which is the standard American moderate-oven setting.
At what temperature do Celsius and Fahrenheit read the same?
−40. It is the one point where the two scales cross, so −40 °C and −40 °F are the same cold.
Why doesn't 'double it and add 30' work for cooking?
It approximates ×1.8 with ×2, so the error grows with the number. At 20 °C it is 2 degrees out; at 200 °C it is 38 degrees out, which is the difference between roasting and burning.
Should I write K or °K?
K on its own. Kelvin is an absolute scale, so it does not take the degree symbol — 300 K, never 300 °K.
Worked example
An American recipe in a European oven
Input: 425 °F → Celsius
Output: 218.3 °C
Note: Most European ovens step in 10s, so you would set 220 °C. The 1.7-degree difference is far smaller than the swing of a domestic oven thermostat.