Temperature Converter

What is temperature conversion?

Temperature conversion translates values between Celsius (used by most countries), Fahrenheit (used in the United States), and Kelvin (used in science). Unlike most unit conversions that involve simple multiplication, temperature conversions require both scaling and offset adjustments because the three scales have different zero points and different degree sizes.

Celsius sets 0 at the freezing point of water and 100 at the boiling point. Fahrenheit sets 32 at freezing and 212 at boiling. Kelvin uses the same degree size as Celsius but starts at absolute zero (-273.15 C), the lowest physically possible temperature where all molecular motion stops.

Conversion formulas

• Celsius to Fahrenheit: F = C * 9/5 + 32.
• Fahrenheit to Celsius: C = (F - 32) * 5/9.
• Celsius to Kelvin: K = C + 273.15.
• Kelvin to Celsius: C = K - 273.15.

How to use this tool

Enter a temperature value in any of the three scales and the equivalent values in the other two scales are calculated instantly. The tool also shows common reference points for context (body temperature, room temperature, water freezing/boiling).

Common temperature reference points

Absolute zero: -273.15 C / -459.67 F / 0 K. Water freezes: 0 C / 32 F / 273.15 K. Room temperature: 20-22 C / 68-72 F. Body temperature: 37 C / 98.6 F. Water boils: 100 C / 212 F / 373.15 K. A quick mental approximation: double the Celsius value and add 30 to get a rough Fahrenheit estimate.

Frequently asked questions

Why does the United States use Fahrenheit?

Fahrenheit was the standard temperature scale when the US became independent. While most countries adopted Celsius as part of the metric system in the 19th and 20th centuries, the US never mandated the switch for everyday use. Fahrenheit arguably provides finer granularity for weather temperatures (0-100 F roughly covers the range of outdoor temperatures experienced in most of the US).

What is the temperature where Celsius and Fahrenheit are equal?

Celsius and Fahrenheit are equal at -40 degrees. You can verify: (-40) * 9/5 + 32 = -72 + 32 = -40. This is the only point where the two scales intersect. It is also extremely cold — about the temperature of winter in northern Siberia or central Antarctica.