Temperature Converter
Convert temperatures between Celsius, Fahrenheit and Kelvin. Type in any scale and the others update instantly.
Type in any field — the other two convert automatically.
How it works
There are three temperature scales in common use, and this tool converts between all of them at once. Type a value into any field and the other two are recalculated instantly.
- Celsius (°C) is used across most of the world for everyday temperatures. Water freezes at 0 and boils at 100.
- Fahrenheit (°F) is common in the United States. Water freezes at 32 and boils at 212.
- Kelvin (K) is the scientific scale, starting at absolute zero. It has no negative values and is used in physics and chemistry.
The conversions follow the standard formulas: Fahrenheit to Celsius subtracts 32 and multiplies by 5/9; Celsius to Kelvin adds 273.15. You don't have to remember any of that — just type and read the result.
When to use
The most frequent need is translating between Celsius and Fahrenheit. Anyone reading a US recipe with oven temperatures in Fahrenheit, checking the weather abroad, or following international content runs into this constantly.
Kelvin shows up in study and science: physics and chemistry problems, and specifications for lighting ("color temperature" in kelvin). Having the three scales side by side covers cooking, travel, weather, schoolwork and technical work without hunting for a separate formula each time.
Practical examples
A US recipe
A recipe says to bake at 350°F. Typing that into the Fahrenheit field shows about 177°C — the setting to use on an oven marked in Celsius.
Room temperature
A comfortable 25°C equals 77°F and about 298 K. Seeing all three at once makes it easy to translate a temperature into whatever scale your context uses.
Common mistakes
The most common mistake is converting Celsius and Fahrenheit by simply adding or subtracting a fixed number. The scales don't just shift — they also stretch differently, so you need both a multiplication and an addition. That's why 20°C isn't 52°F even though 0°C is 32°F.
Another slip is forgetting that Kelvin has no degree symbol and starts at absolute zero. You can't have a negative Kelvin temperature, and 0 K is the coldest anything can be — about −273.15°C.
There's also confusion around body temperature and weather. A "normal" number in one scale can sound alarming in another: 37°C (normal body temperature) is 98.6°F. Reading a value in the wrong scale leads to needless worry or the opposite.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. For example, 20°C × 9/5 + 32 = 68°F. The tool does this automatically as you type.
What is Kelvin used for?
Kelvin is the scientific scale, starting at absolute zero. It's used in physics, chemistry and to describe the "color temperature" of light. To go from Celsius to Kelvin, add 273.15.
What is a normal body temperature in Fahrenheit?
About 98.6°F, which corresponds to 37°C. Values are considered feverish above roughly 100.4°F (38°C), though it varies by person and measurement method.
Can temperatures be negative in all scales?
Celsius and Fahrenheit can go negative, but Kelvin cannot: it starts at absolute zero, the lowest possible temperature, so its values are always zero or above.
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