Temperature Converter
Convert a temperature between degrees Celsius, degrees Fahrenheit and kelvin.
Result
20 °C
Please note: The result is an estimate and has been rounded. Actual costs and values may differ, and no rights can be derived from this calculation.
How this number is calculated
The blocks use your input. Change a value above and they update with it.
Step 1 · In kelvin
Step 2 · Result
How the calculation works
Convert a temperature between degrees Celsius, degrees Fahrenheit and kelvin. Enter the temperature, choose which scale to convert from and to, and see the result at once. The button swaps From and To.
The calculator first converts your temperature to kelvin, the scale that starts at absolute zero. For Celsius it subtracts absolute zero of −273.15 °C, so it adds 273.15. For Fahrenheit it subtracts absolute zero of −459.67 °F and divides by 1.8, because a degree Fahrenheit is 1.8 times smaller than a kelvin. A temperature in kelvin stays the same. The scale you choose follows from kelvin. The result is rounded to two decimals. A temperature below absolute zero does not exist and gives a message.
Formula
°F = °C × 1.8 + 32. °C = (°F − 32) ÷ 1.8. K = °C + 273.15. °C = K − 273.15.
Assumptions
- A degree Celsius is the same size as a kelvin and exactly 1.8 times the size of a degree Fahrenheit.
- Absolute zero is 0 K, −273.15 °C and −459.67 °F. A lower temperature gives an error.
- You enter a temperature, not a temperature difference. For a difference, only the factor 1.8 applies, without the 32.
- Only the results are rounded, to two decimal places, with halves rounded away from zero.
Example calculations
The button fills in the calculator above, so you can carry on from there.
-
Oven at 350 °F
Result
176.67 °C
Temperature 350 · Fahrenheit · Celsius
A common oven temperature in American recipes.
-
Body temperature 98.6 °F
Result
37 °C
Temperature 98.6 · Fahrenheit · Celsius
-
Summer day at 86 °F
Result
30 °C
Temperature 86 · Fahrenheit · Celsius
Frequently asked questions
How do I convert Fahrenheit to Celsius?
Subtract 32 and divide by 1.8: 100 °F is (100 − 32) ÷ 1.8 = 37.78 °C. The other way round, multiply Celsius by 1.8 and add 32. For a rough estimate in your head, subtract 30 and halve.
What is 180 °C in Fahrenheit?
180 °C is 356 °F, because 180 × 1.8 + 32 = 356. American recipes usually give this oven temperature as 350 °F, which is 176.67 °C.
What is 37 °C in Fahrenheit?
37 °C is 98.6 °F, the well-known figure for normal body temperature. A temperature of 38 °C, which is 100.4 °F, or higher counts as a fever.
What is absolute zero?
It is the lowest possible temperature: 0 K, which equals −273.15 °C and −459.67 °F. Nothing can be colder, so the calculator rejects lower values. Laboratories have come extremely close, but it can never be fully reached.
At what temperature are Celsius and Fahrenheit the same?
At −40 degrees: −40 °C is exactly −40 °F. Above −40 the Fahrenheit number is always higher than the Celsius number, below it the Fahrenheit number is lower.
How do I convert Celsius to kelvin?
Add 273.15: 20 °C is 293.15 K. A step of 1 kelvin is the same size as 1 degree Celsius. Kelvin is written as K, without a degree sign.
Sources and checks
Sources
- NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically
- The International System of Units (SI), 9th edition (BIPM SI Brochure)
How we check it
This calculator has 23 fixed checks: 16 calculations with a result that is fixed in advance, and 7 cases of invalid input that must be rejected. They all run automatically every time we publish; if one fails, the calculator does not go live.
See the calculations
- Temperature 68 · Fahrenheit · Celsius → Result 20 °C
- Temperature 100 · Celsius · Fahrenheit → Result 212 °F
- Temperature 0 · Celsius · Fahrenheit → Result 32 °F
- Temperature -40 · Celsius · Fahrenheit → Result -40 °F
- Temperature -40 · Fahrenheit · Celsius → Result -40 °C
- Temperature 100 · Fahrenheit · Celsius → Result 37.78 °C
- Temperature 300 · Kelvin · Celsius → Result 26.85 °C
- Temperature 0 · Kelvin · Celsius → Result -273.15 °C
- Temperature -273.15 · Celsius · Fahrenheit → Result -459.67 °F
- Temperature -459.67 · Fahrenheit · Celsius → Result -273.15 °C
Changes
- : New layout: from and to with a swap button, one result and a two-step explanation. Sources added and content reviewed.
- : First version.
Last reviewed: · How we build and check our calculators
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