The three scales share the same physics, only their zero points and step sizes differ. Water freezes at 0 °C, 32 °F and 273.15 K; a Celsius degree and a Kelvin are the same size, while a Fahrenheit degree is 5/9 as large. This tool converts through Celsius as a pivot, so every pairing - C to F, F to C, C to K, K to F and so on - uses the same exact constants and stays consistent. Choose the starting scale, type a value (a dot or a comma both work as the decimal mark), and the big number plus the three-way panel update instantly. Nothing is uploaded; the math runs on the page.
Private browser utility / Converters
Temperature Converter
Runs entirely in your browser - no upload, no sign-up.
Convert from
ResultEnter a temperature to convert
How do you convert a temperature between Celsius, Fahrenheit and Kelvin?
Pick the scale you're starting from and type the number. To go from Celsius to Fahrenheit, multiply by 9/5 and add 32; to reach Kelvin, add 273.15. This free converter does every direction as you type and shows all three scales at once, entirely in your browser.
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How to use
- 01Pick the starting scale
Choose °C, °F or K in the 'Convert from' selector so the tool knows which scale your number is in.
- 02Type the temperature
Enter a number in the field. Decimals and negative values are fine - use a dot or a comma, e.g. 25 or -12,5.
- 03Read all three scales
The primary result appears as a big number, with Celsius, Fahrenheit and Kelvin shown together beneath it. Use Copy result to grab all three.
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Who it's for
- Cooking and baking - convert an oven or recipe temperature written in one scale into the one your oven uses, e.g. 180 °C to 356 °F.
- Weather and travel reading a forecast in Celsius when you think in Fahrenheit, or the reverse, before you pack.
- Fever and health checks turning a body temperature like 37 °C into 98.6 °F, or 100.4 °F back into 38 °C.
- Science and homework converting lab readings between Celsius and Kelvin, where absolute zero (0 K) is the floor.
- Engineering and HVAC moving set-points and readings between metric and imperial temperature scales.
FAQ
Is the temperature converter free?
Yes - it's 100% free, with no sign-up and no limits. Every conversion runs entirely in your browser and nothing you type is uploaded or stored.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (that is 1.8) and add 32. So 25 °C is 25 × 1.8 + 32 = 77 °F, and 37 °C is 98.6 °F. This tool does it instantly and also shows the Kelvin value.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. So 98.6 °F is (98.6 - 32) × 5/9 = 37 °C, and 212 °F is 100 °C. Select °F as the starting scale and the tool handles it for you.
How do I convert Celsius to Kelvin?
Add 273.15. So 0 °C is 273.15 K and 100 °C is 373.15 K. The size of one Kelvin is identical to one Celsius degree, so the two scales only differ by that fixed offset.
What is 0 Kelvin in Celsius and Fahrenheit?
0 K is absolute zero, which is -273.15 °C and -459.67 °F. Nothing can be colder, so any conversion that produces a temperature below this is physically impossible - the tool warns you when that happens.
At what temperature are Celsius and Fahrenheit equal?
At -40 degrees: -40 °C is exactly -40 °F. It is the single point where the two scales meet, which makes it a handy way to check a conversion is set up correctly.
Why does Kelvin not use a degree symbol?
Because Kelvin is an SI base unit, not a scale of degrees relative to a reference. It is written '300 K', spoken as '300 kelvin', while Celsius and Fahrenheit keep the degree sign (°C, °F).