Temperature Converter
Convert Celsius, Fahrenheit, Kelvin and Rankine with the formula shown and a check against absolute zero — the conversion most calculators get wrong.
Converts temperature points, not differences: a gap of 10 °C is a gap of 18 °F, not 50 °F.
Category: Temperature
This converts temperature readings, not temperature differences: a 10 °C difference equals an 18 °F difference, not 50 °F.
Result
Absolute zero is −273.15 °C = −459.67 °F = 0 K = 0 °R.
All units
| Unit | Symbol | Value | Copy |
|---|---|---|---|
| Metric | |||
| Celsius | °C | 1 | |
| Kelvin | K | 274.15 | |
| Imperial & UK | |||
| Fahrenheit | °F | 33.8 | |
| Other | |||
| Rankine | °R | 493.47 | |
Conversion factors for every unit
One of each unit expressed in the base unit of this category (Kelvin).
°F = °C × 9/5 + 32 · K = °C + 273.15 · °R = K × 9/5
Absolute zero is −273.15 °C = −459.67 °F = 0 K = 0 °R.
How to use
- The page opens on Temperature with °C → °F (°F → °C in the US); swap the units if needed.
- Type the temperature in Value — Celsius, Fahrenheit, Kelvin and Rankine all update.
- Use ⇄ Swap to reverse the pair, and Precision to fix the number of significant digits.
- Below the result you get the formula, and a warning if the value is below absolute zero.
- Copy the converted value or any row of the unit table, or use Share link to send it on.
FAQ
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32: °F = °C × 9/5 + 32. So 20 °C is 68 °F. To go the other way, subtract 32 first and then multiply by 5/9.
What is absolute zero?
Absolute zero is the lowest possible temperature: 0 K, which is −273.15 °C, −459.67 °F or 0 °R. Nothing can be colder, so this converter rejects any input below it instead of returning a meaningless number.
Why is a temperature difference converted differently?
Because the scales have different zero points. A reading of 10 °C is 50 °F, but a difference of 10 °C is a difference of 18 °F (10 × 9/5), with no +32 offset. This tool converts readings, not intervals.
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