Convert Celsius to Fahrenheit

Celsius to Fahrenheit: the formula and an example

To turn degrees Celsius into degrees Fahrenheit, multiply by 9/5 (that is 1.8) and add 32: °F = °C × 9/5 + 32. Example: 25 °C is 25 × 1.8 + 32 = 77 °F.

The converter on this page is already set to Celsius to Fahrenheit. Type a temperature and the answer updates as you type, with the formula underneath and a table that also gives the value in kelvin. The swap button flips the conversion to Fahrenheit to Celsius. Results are rounded to six significant figures, and a message warns you when a value falls below absolute zero, −273.15 °C.

Celsius to Fahrenheit conversion chart

Weather, body temperature, ovens: where you will meet Celsius

Traveling abroad. Outside the United States, nearly every forecast is given in Celsius. Three anchors cover most trips: 0 °C is freezing (32 °F), 20 °C is a mild 68 °F, and 30 °C is a hot 86 °F.

Body temperature. A thermometer bought in Europe reads in Celsius: 37 °C is 98.6 °F and 38 °C is 100.4 °F.

Oven settings. A European recipe that says 180 °C means 356 °F. Ovens marked in Fahrenheit move in 25-degree steps, so set 350 °F. Likewise, 150 °C becomes 300 °F, 200 °C becomes 400 °F and 220 °C becomes 425 °F.

Mental math: double it and add 30

The usual shortcut is to double the Celsius figure and add 30. For 20 °C that gives 20 × 2 + 30 = 70 °F, while the exact answer is 68 °F. You are off by 2 °F.

The shortcut is exact at 10 °C (50 °F) and drifts as it gets hotter: 4 °F too high at 30 °C (90 instead of 86). Do not use it for baking: at 200 °C it says 430 °F when the real figure is 392 °F, a 38 °F error.

Frequently asked questions

At what temperature are Celsius and Fahrenheit the same?

At −40. Check it with the formula: −40 × 1.8 + 32 = −40. It is the only point where both scales show the same number.

Why do you add 32?

Because the two scales do not start from the same zero: water freezes at 0 °C but at 32 °F. Between freezing and boiling there are 100 Celsius degrees and 180 Fahrenheit degrees, which is where the 9/5 ratio comes from.

Is a temperature difference converted the same way?

No. For a difference, multiply by 1.8 and leave out the 32. If the temperature rises by 5 °C, it rises by 9 °F.