Converter Tools

Temperature Converter

Convert temperature between Celsius, Fahrenheit, and Kelvin.

How to use the Temperature Converter

Enter value

Type a temperature value in any unit.

Select unit

Choose the input unit (Celsius, Fahrenheit, or Kelvin).

View results

See automatic conversions to all other units.

What is a Temperature Converter?

A temperature converter changes a temperature between Celsius, Fahrenheit, and Kelvin. Type a value in one scale and read it in the others instantly, with the conversion formula shown so you can see how the number was reached.

The common need is Celsius to Fahrenheit and back: most of the world uses Celsius while the United States uses Fahrenheit, so recipes, weather, medical readings, and travel constantly cross the two. Kelvin is the scientific scale where zero is absolute zero.

Convert Celsius, Fahrenheit, and Kelvin
Instant results as you type
Shows the conversion formula and working
Handles negatives and decimals precisely
Convert in any direction between scales
Runs in your browser, no signup

Celsius to Fahrenheit and back

To go from Celsius to Fahrenheit, multiply by 9/5 and add 32: 20°C becomes 68°F. To go back, subtract 32 then multiply by 5/9: 98.6°F becomes 37°C, normal body temperature. A quick mental shortcut is to double the Celsius value and add 30, which gets you close enough for weather, though the converter gives the exact figure.

The reference points worth memorizing

Water freezes at 0°C, 32°F, and 273.15 K. It boils at 100°C, 212°F, and 373.15 K at sea level. Body temperature is 37°C or 98.6°F. A comfortable room is around 20 to 22°C or 68 to 72°F. The two scales happen to meet at minus 40, where minus 40°C equals minus 40°F exactly.

Why Kelvin has no degrees

Kelvin starts at absolute zero, the point where molecular motion stops, so it needs no negative numbers and is written without the degree symbol: 300 K, not 300°K. It shares Celsius's step size, so a change of one kelvin equals a change of one degree Celsius. Science and engineering use it because ratios of Kelvin values are physically meaningful in a way Celsius and Fahrenheit are not.

Frequently Asked Questions

How do I convert Celsius to Fahrenheit?

Multiply the Celsius value by 9/5 and add 32. For example, 25°C times 1.8 is 45, plus 32 gives 77°F. The converter does this instantly and shows the steps.

What is the formula for Fahrenheit to Celsius?

Subtract 32 from the Fahrenheit value, then multiply by 5/9. So 50°F minus 32 is 18, times 5/9 gives 10°C.

What is normal body temperature in both scales?

37°C, which equals 98.6°F. A reading is generally considered a fever above about 38°C or 100.4°F.

Why is there no degree symbol on Kelvin?

Kelvin is an absolute scale measured from absolute zero, so its values are written as plain numbers with a K, like 300 K, by scientific convention.

At what temperature are Celsius and Fahrenheit equal?

At minus 40. Minus 40°C is exactly minus 40°F, the single point where the two scales cross.

Does the converter handle negative temperatures?

Yes. Sub-zero values in any scale convert correctly, including readings below absolute zero being flagged as physically impossible.

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What is a Temperature Converter?

Convert Celsius, Fahrenheit, and Kelvin

Instant results as you type

Shows the conversion formula and working

Handles negatives and decimals precisely

Convert in any direction between scales

Runs in your browser, no signup