Celsius to Fahrenheit Converter

20 °C in Fahrenheit: 68 °F
Kelvin: 293.15 K
Rankine: 527.67 °R
Réaumur: 16 °Ré
Rømer: 18 °Rø
Newton: 6.6 °N
Delisle: 120 °De

What it does

Convert a temperature between Celsius, Fahrenheit and Kelvin, and the specialist and historical scales: Rankine, Réaumur, Rømer, Newton and Delisle. Enter it in whichever scale you have and see it in all the others.

How to use it

Temperature: The temperature to convert. Choose its scale in the Units box: °C, °F, kelvin, or one of the specialist scales (Rankine, Réaumur, Rømer, Newton, Delisle).

Common uses

Following a recipe or oven setting from another country.
Understanding weather forecasts and body temperatures abroad.
Converting other measurements.

The formula

°F = °C × 9 ÷ 5 + 32°C = (°F − 32) × 5 ÷ 9K = °C + 273.15°R = K × 9 ÷ 5°Ré = °C × 4 ÷ 5°Rø = °C × 21 ÷ 40 + 7.5°N = °C × 33 ÷ 100°De = (100 − °C) × 3 ÷ 2

Where:

9 ÷ 5: 1.8: one degree Celsius is 1.8 degrees Fahrenheit

A quick estimate: double the Celsius and add 30. It's close for everyday weather temperatures.

Worked example

To convert 100 °C to Fahrenheit, multiply by 9 ÷ 5 and add 32:

100 × 1.8 = 180
180 + 32 = 212 °F
In kelvin: 100 + 273.15 = 373.15 K

Questions people ask

What are some common temperatures in both units?

Water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F) at sea level. Normal body temperature is about 37 °C (98.6 °F), a warm day is 25 °C (77 °F) and a moderate oven is 180 °C (356 °F).

When are Celsius and Fahrenheit the same?

At −40. −40 °C is exactly −40 °F.

What are Kelvin, Rankine and the other scales?

Kelvin and Rankine start at absolute zero, the coldest possible temperature: Kelvin uses Celsius-sized degrees (used in science), Rankine uses Fahrenheit-sized ones (some US engineering). Réaumur, Rømer, Newton and Delisle are historical scales. Delisle runs backwards: higher numbers are colder.

Last checked 24 October 2026