When to use it
Use this converter to switch between Celsius, Fahrenheit, Kelvin and Rankine. It is useful when following a recipe from another country, reading a weather forecast abroad, setting an oven, checking a fever reading, or doing science homework that uses Kelvin.
How to use it
- Enter the temperature in Value. Negative numbers are fine, such as −5.
- Choose the scale you have, such as Celsius (°C).
- Choose the scale you want, such as Fahrenheit (°F).
- Read the result, or click Copy result.
- Use the swap button to convert the other way.
The All conversions table shows the same temperature in all four scales at once.
Worked example
A weather forecast for Lisbon says 20 °C and you are used to Fahrenheit. Enter 20 with Celsius and Fahrenheit selected. The result is 68 °F, a mild spring day. The table also shows 293.15 K and 527.67 °R.
Now an American recipe says to bake at 350 °F. Swap the units, enter 350, and the result is about 176.7 °C. Most ovens have marks every 10 degrees, so set it to 180 °C, or 160 °C for a fan oven.
Handy reference points
- Water freezes at 0 °C, 32 °F or 273.15 K.
- Body temperature is about 37 °C, or 98.6 °F.
- Water boils at 100 °C, or 212 °F, at sea level.
- A warm summer day of 30 °C is 86 °F.
Fever and health readings
A normal body temperature is about 36.1 to 37.2 °C (97 to 99 °F). Many guides treat 38 °C, or 100.4 °F, as a fever. If a thermometer reads in a unit you are not used to, convert it here, and follow your doctor’s advice on what to do next.
Tips
- Remember fan ovens. Fan or convection ovens usually need about 20 °C (25 °F) less than recipes written for conventional ovens.
- Watch the minus sign. −10 °C is 14 °F, while 10 °C is 50 °F.
- Use Kelvin without a degree sign. Scientists write 300 K, not 300 °K.
Common mistakes
- Converting a temperature difference like a temperature. A rise of 10 °C is a rise of 18 °F, not 50 °F, because the +32 only applies to actual temperatures.
- Forgetting to round oven settings. Ovens are not that precise, so the nearest 5 or 10 degrees is fine.
- Mixing up °F and °C on thermometers. Many show both scales, so check which side you are reading.