Value, From, To
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How this calculator works
Temperature scales differ in both step size and zero point, so converting takes a multiplication and an offset. A Celsius degree is the same size as a kelvin and 1.8 times a Fahrenheit degree. Kelvin starts at absolute zero, the lowest temperature possible.
Formula
- °F = °C × 9/5 + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15
Worked example
100 °C to °F
- Value
- 100
- From
- Celsius (°C)
- To
- Fahrenheit (°F)
Result212 °F
100 °C = 212 °F.
Common reference points
| Celsius | Fahrenheit | Kelvin | |
|---|---|---|---|
| Absolute zero | −273.15 °C | −459.67 °F | 0 K |
| Water freezes | 0 °C | 32 °F | 273.15 K |
| Room temperature | 20 °C | 68 °F | 293.15 K |
| Body temperature | 37 °C | 98.6 °F | 310.15 K |
| Water boils (sea level) | 100 °C | 212 °F | 373.15 K |
Frequently asked questions
How do I convert Celsius to Fahrenheit quickly?
Multiply by 1.8 and add 32. For a rough mental estimate, double the Celsius value and add 30.
At what temperature are Celsius and Fahrenheit equal?
At −40 degrees. −40 °C is the same as −40 °F.
What is absolute zero?
0 K, equal to −273.15 °C or −459.67 °F. Temperatures below it are not physically possible.
Sources
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Results are estimates based on the values you enter and the published method shown above. They do not replace professional medical, financial or legal advice. Method reviewed October 7, 2026. About this site