How to use the temperature converter
- 1 Type the temperature, for example 37 or −10.
- 2 Choose the scale you are converting from.
- 3 Choose the scale you want to see; the result appears at once.
- 4 Check the table for the same temperature in all four scales.
Temperatures to remember
- Formulas: °F = °C × 9/5 + 32, and °C = (°F − 32) × 5/9. Kelvin is °C + 273.15.
- Quick estimate: double the Celsius figure and add 30 for a rough Fahrenheit value; it is close for everyday weather.
- Body temperature: about 37 °C or 98.6 °F; most doctors treat 38 °C, 100.4 °F, or above as a fever.
- Ovens: 180 °C is 356 °F, usually rounded to 350 °F or gas mark 4. Fan ovens need about 20 °C less.
- Same number: −40 is the same in both Celsius and Fahrenheit.
Converting a recipe's weights too? Use the Weight Converter. Converting lengths? Try the Length Converter.
Features
Four scales
Celsius, Fahrenheit, Kelvin and Rankine, converted through Kelvin for accuracy.
Formula shown
See the conversion written out so you can check or learn it.
Negative values
Works below freezing and below zero Fahrenheit.
When to use it
Weather
Convert a US forecast in °F to °C, or the other way round, when travelling. Convert recipe weights with the Weight Converter.
Cooking
Turn 350 °F in a recipe into about 177 °C for your oven. Convert distances with the Length Converter.
Health
Check a fever: 38 °C is 100.4 °F.
Science and school
Convert to Kelvin for physics and chemistry problems.
Related Unit tasks
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For example, 25 °C × 9/5 + 32 = 77 °F.
How do I convert Fahrenheit to Celsius?
Subtract 32 and multiply by 5/9. For example, (98.6 − 32) × 5/9 = 37 °C.
What is Kelvin?
The SI temperature scale, starting at absolute zero. 0 °C is 273.15 K, and a change of 1 K equals a change of 1 °C.
At what temperature are Celsius and Fahrenheit equal?
At −40. −40 °C is exactly −40 °F.
What oven temperature is 180 °C?
About 356 °F, usually set as 350 °F, or gas mark 4.
How do I convert oven temperatures to gas marks?
Gas mark 1 is about 140 °C (275 °F), and each mark adds roughly 14 °C or 25 °F, so gas mark 4 is about 180 °C (350 °F) and gas mark 6 about 200 °C (400 °F). Fan ovens are usually set about 20 °C lower than conventional ovens for the same recipe.
Why does water boil at a lower temperature in the mountains?
Air pressure is lower at altitude, so water boils below 100 °C (212 °F). At about 2,000 metres it boils near 93 °C, which is why cooking times are longer in high places.
What is normal body temperature?
About 37 °C or 98.6 °F, though anything from about 36.1 °C to 37.2 °C is normal for most adults. A fever usually starts at 38 °C, which is 100.4 °F.
What is absolute zero?
The lowest possible temperature: 0 K, which is −273.15 °C or −459.67 °F. The Kelvin and Rankine scales both start there.
What is Rankine used for?
Rankine is an absolute scale with Fahrenheit-sized degrees, still used in some US engineering, especially thermodynamics.
How do I convert Celsius to Kelvin?
Add 273.15. For example, 25 °C is 298.15 K. To go back, subtract 273.15.
What is room temperature in Fahrenheit?
Room temperature is usually taken as about 20 to 22 °C, which is 68 to 72 °F. Fridges are kept at about 4 °C, or 39 °F, and freezers at −18 °C, which is 0 °F.
How do I convert a temperature difference?
A change of 1 °C equals a change of 1.8 °F, with no 32 added. So a 10 °C rise is an 18 °F rise. Only add or subtract 32 when converting an actual temperature.
Built and reviewed by Hamza Farooq, founder and lead developer
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