Celsius
°C
Fahrenheit
°F
Kelvin
K
Rankine
°R
Click any field to use it as your input — all other units update instantly.
Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin and Rankine. Instant temperature conversion.
How to convert temperatures online for free
- Type a temperature into the Celsius, Fahrenheit, or Kelvin field (no signup needed)
- All scales update instantly — Celsius, Fahrenheit, Kelvin, and Rankine
- Click any result to copy it, useful for cooking, weather, and science unit conversions
Why use our Temperature Converter?
Temperature is one of the few unit conversions where the formula is non-trivial — the Celsius/Fahrenheit conversion involves both multiplication and addition, making mental maths unreliable. Our converter does the calculation precisely with no rounding surprises.
Common uses: reading a weather forecast in an unfamiliar scale, cooking from a recipe that uses a different temperature unit than your oven, or understanding medical temperature readings (37°C = 98.6°F).
Everything runs in your browser. No account, no ads on the tool, completely free.
Frequently asked questions
- How do I convert Celsius to Fahrenheit?
- Use the formula: °F = (°C × 9/5) + 32. For example, 20°C = (20 × 1.8) + 32 = 68°F. Type in the Celsius field above and Fahrenheit updates instantly.
- How do I convert Fahrenheit to Celsius?
- Use the formula: °C = (°F − 32) × 5/9. For example, 98.6°F = (98.6 − 32) × 5/9 = 37°C (body temperature).
- What is absolute zero in Celsius and Fahrenheit?
- Absolute zero is 0 Kelvin, which equals −273.15°C or −459.67°F. It is the lowest theoretically possible temperature.
- At what temperature do Celsius and Fahrenheit meet?
- Celsius and Fahrenheit are equal at −40°. So −40°C = −40°F. This is a useful memory aid for the conversion formula.
- What temperature does water boil in Fahrenheit?
- Water boils at 212°F (100°C) at standard atmospheric pressure (1 atm / 101.325 kPa). At higher altitudes, the boiling point is lower.
- What is Rankine and when is it used?
- Rankine (°R) is an absolute temperature scale using Fahrenheit-sized degrees. It is used in some US engineering applications. 0 °R = absolute zero; water boils at 671.67 °R.