Temperature Converter (°C ↔ °F ↔ °K ↔ °R)
Convert between Celsius, Fahrenheit, Kelvin and Rankine instantly — including the exact formulas.
100% free
No sign-up
Private · runs in your browser
How to use the free online temperature converter
- Enter a temperature value.
- Pick the input scale.
- See all other scales instantly.
- Copy any result with one click.
About this tool
Convert temperatures between Celsius, Fahrenheit and Kelvin with live results as you type. Includes the exact formulas, common reference points (freezing, boiling, body temperature) and instant reverse conversion. Perfect for cooking, travel, weather, science homework and HVAC work.
Key features
- 4 temperature scales
- Formulas shown
- Instant live conversion
- Works offline
Privacy first: every calculation and generation runs 100% locally in your web browser using the Web Crypto API. Your input never touches a server — nothing is stored, logged or sold.
Frequently asked questions
°F = °C × 9/5 + 32. For example, 20 °C = 68 °F. Kelvin is simply °C + 273.15.
Both use the same degree size; Kelvin is an absolute scale starting at absolute zero (−273.15 °C), so it has no negative values.
The two scales cross at −40, because the conversion offset of 32 exactly cancels at that point.
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