Celsius to Fahrenheit Converter

Use this free Celsius to Fahrenheit converter to change a temperature from degrees Celsius to degrees Fahrenheit. Type a number in the Celsius box and the Fahrenheit answer appears as you type, with the working shown step by step and a quick estimate you can do in your head. You can also type in the Fahrenheit box to go the other way. Pick how many decimals to round to and copy a link to your conversion. Tables list a chart from −40 °C to 100 °C, the Celsius values people look up most, key temperatures, and body temperature in tenths of a degree. It is free and instant, and your numbers stay in your browser.

How to convert Celsius to Fahrenheit

Temperature scales do not start at the same point, so you cannot just multiply. You multiply and then add a fixed amount. To change Celsius to Fahrenheit, multiply by 9/5 (that is 1.8) and add 32.

For 25 °C: 25 × 1.8 = 45, and 45 + 32 = 77 °F. For 0 °C: 0 × 1.8 = 0, and 0 + 32 = 32 °F, the freezing point of water. For 100 °C, the boiling point at sea level: 100 × 1.8 = 180, and 180 + 32 = 212 °F.

A quick way without a calculator

Double the Celsius number and add 30. For 20 °C that gives 20 × 2 + 30 = 70 °F, close to the exact 68 °F. It is exact at 10 °C (50 °F) and drifts higher as it gets hotter: at 30 °C it gives 90 °F against an exact 86 °F, and at 35 °C it gives 100 °F against 95 °F. It is fine for judging the weather, but use the exact formula for cooking and science.

Common conversions

0 °C is 32 °F, 20 °C is 68 °F, 25 °C is 77 °F, 30 °C is 86 °F, 37 °C is 98.6 °F, 40 °C is 104 °F and 100 °C is 212 °F. The chart above lists more, from −40 °C to 100 °C, and the table of most searched values shows the ones people look up most.

Oven temperatures

Recipes written in Celsius need a Fahrenheit setting in a US oven. 180 °C is 356 °F, which US recipes usually round to 350 °F. 200 °C is 392 °F and 220 °C is 428 °F. A fan (convection) oven may need about 20 °C less, so check your oven's manual. The Temperature Converter has a full table of oven settings.

Body temperature in tenths

Thermometers often show tenths of a degree. 36.6 °C is 97.88 °F, 37 °C is 98.6 °F and 38 °C is 100.4 °F. The table above lists every tenth from 36 °C to 38 °C. It is a guide for converting a reading, not medical advice: if you are worried about a temperature, ask a doctor or nurse.

Celsius, Fahrenheit and the spelling

The correct spellings are Celsius and Fahrenheit, after the two scientists who gave their names to the scales. Many people type "celcius" or "farenheit", and this page is for them too. A Celsius degree is bigger than a Fahrenheit degree: a change of 1 °C is a change of 1.8 °F. Water freezes at 0 °C and 32 °F and boils at 100 °C and 212 °F, which is 100 steps in Celsius and 180 steps in Fahrenheit.

Fahrenheit to Celsius

To go the other way, subtract 32 and multiply by 5/9: °C = (°F − 32) × 5/9. For 72 °F that is 40 × 5/9 = 22.22 °C. You can do it here too: type the number in the Fahrenheit box and the Celsius box shows the answer, or use the Fahrenheit to Celsius converter, which has its own chart and oven temperatures.

When the two scales are equal

At −40 the two scales show the same number: −40 °C is exactly −40 °F. It is the only point where they agree. Nothing can be colder than absolute zero, which is −273.15 °C or −459.67 °F, so the converter does not accept anything below it.