Temperature Converter
Convert Celsius, Fahrenheit, Kelvin and Rankine with one click.
The Temperature Converter switches between Celsius, Fahrenheit, Kelvin and Rankine — the four scales you meet in weather forecasts, cooking, science and engineering. Type a number and choose the units; because temperature scales have different zero points, the tool uses the proper affine formulas rather than a simple multiplier.
The conversions people check most — 25 °C is 77 °F, 100 °C boils at 212 °F, body temperature 98.6 °F is 37 °C — all come out exactly right, including negative values and decimals, which is where quick mental math fails (and where naive converters get -40 wrong: -40 °C equals -40 °F).
Kelvin is the SI base unit used in science, with absolute zero at 0 K (−273.15 °C), and Rankine is its Fahrenheit-based counterpart used in some US engineering. All conversions run locally in your browser.
Result
1 °C = 33.8 °F
1 °C = 33.8 °F
1 °F = -17.2222222222 °C
How to use the Temperature Converter
- Type the temperature value (negative values work fine).
- Choose the scale you are converting from.
- Choose the scale you want the answer in.
- Read the converted temperature and the unit rate where relevant.
- Swap the units to check the reverse direction.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32: °F = °C × 1.8 + 32. So 20 °C → 68 °F. To go the other way: °C = (°F − 32) × 5/9.
At what temperature are Celsius and Fahrenheit equal?
At −40 degrees: −40 °C = −40 °F. This happens because the two scales' slopes and offsets cross exactly once. A converter that multiplies instead of using the offset formula gets this wrong — this one does not.
What is Kelvin used for?
Kelvin is the SI unit of thermodynamic temperature, used throughout science and engineering because 0 K is absolute zero — the point of minimum possible energy. Water freezes at 273.15 K and boils at 373.15 K. Kelvin has no degree symbol and no negative values.
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