Temperature Converter
Type a temperature, choose its unit and see it in Celsius, Fahrenheit, Kelvin and Rankine at once. The conversions are exact, so 98.6 degrees Fahrenheit is exactly 37 degrees Celsius, and you choose how many decimals to round to. A table shows common temperatures, and a value below absolute zero is reported as an error. Everything runs in your browser.
Common temperatures
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Format ConversionAbout the Temperature Converter
The temperature converter uses exact fractions instead of floating point numbers, so there are no tiny errors such as 36.99999999999999. To go from Celsius to Fahrenheit it multiplies by 9/5 and adds 32, and to go from Fahrenheit to Celsius it subtracts 32 and multiplies by 5/9. Kelvin is Celsius plus 273.15, so 0 K is -273.15 degrees Celsius, and Rankine is Fahrenheit plus 459.67, so 0 R is -459.67 degrees Fahrenheit. A Rankine degree is the same size as a Fahrenheit degree, and a Kelvin is the same size as a Celsius degree. The tool converts everything through Kelvin, rounds the results half up to the decimals you pick, and tells you when a result was rounded. Celsius and Fahrenheit meet at -40. Nothing can be colder than absolute zero, so a value below it is rejected with an explanation. Input is read strictly: a unit written after the number, a comma or an exponent is reported instead of guessed. The results were compared with the Fraction and Decimal types of Python on 60,000 random temperatures in all four units and several decimal settings, including 12,000 below absolute zero, and match. Everything runs in your browser and nothing is uploaded.
How do I convert Celsius to Fahrenheit?▾
Multiply the Celsius value by 9/5, which is 1.8, and add 32. So 100 degrees Celsius is 100 times 1.8 plus 32, which is 212 degrees Fahrenheit. To go back, subtract 32 and multiply by 5/9.
At what temperature are Celsius and Fahrenheit the same?▾
At -40. Put -40 into either formula and you get -40 back. It is the only temperature where the two scales show the same number.
How do I convert Celsius to Kelvin?▾
Add 273.15. So 0 degrees Celsius is 273.15 K, and 100 degrees Celsius is 373.15 K. A change of one kelvin is the same size as a change of one degree Celsius, only the zero point is different.
What is absolute zero?▾
It is 0 K, which is -273.15 degrees Celsius or -459.67 degrees Fahrenheit, the lowest temperature there can be. The converter reports an error for anything below it.
Is my data uploaded?▾
No. The conversion runs in your browser, and what you type is not sent anywhere or stored.