TOOLConvert between temperature scales
Enter a temperature in Celsius, Fahrenheit or Kelvin and see it in the other two instantly. Unlike length or weight, temperature scales don't share a zero point, so the conversion involves both a multiply and an offset — this tool handles that for you and shows all three scales at once.
The formulas
Handy reference points: water freezes at 0°C / 32°F / 273.15 K and boils at 100°C / 212°F / 373.15 K. Normal body temperature is about 37°C / 98.6°F.
How temperature conversion works
Temperature is the one conversion that isn't a simple multiplication, because the scales don't share a zero point. Celsius and Fahrenheit need both a scale factor and an offset:
Worked examples: 20°C is (20 × 9/5) + 32 = 68°F, and 100°F is (100 − 32) × 5/9 = 37.8°C. The two scales meet at −40°, which reads the same in both.
Reference points worth knowing
A few everyday temperatures make good mental anchors:
- Water freezes: 0°C = 32°F
- Comfortable room: 20°C = 68°F
- Body temperature: 37°C ≈ 98.6°F
- Water boils: 100°C = 212°F
- Moderate oven: 180°C ≈ 356°F (gas mark 4)
Most temperature searches come from cooking with an overseas recipe, checking a fever, or travel. For a step-by-step guide to the most common one, read Celsius to Fahrenheit, or convert other units with the length and weight converters.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 (1.8) and add 32. For example, 20°C × 1.8 + 32 = 68°F.
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit temperature and multiply by 5/9. For example, (98.6 − 32) × 5/9 = 37°C.
What is Kelvin and how does it relate to Celsius?
Kelvin is the absolute temperature scale used in science, starting at absolute zero. It shares the same degree size as Celsius, so Kelvin = Celsius + 273.15. Water freezes at 273.15 K.