--- title: "Temperature Converter - Celsius, Fahrenheit, Kelvin | CanDoYa" description: "Free temperature converter for Celsius, Fahrenheit and Kelvin. Type a value and get all three scales at once, with the formula shown - instant, no sign-up, runs in your browser." url: https://candoya.com/tools/temperature-converter/ locale: en type: browser-tool --- # Temperature Converter Category: Converters ## 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. 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. ## How to use it 1. **Pick the starting scale** - Choose °C, °F or K in the 'Convert from' selector so the tool knows which scale your number is in. 2. **Type 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. 3. **Read 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. ## 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. ## Expert note A quick sanity check most people miss: -40 is the one temperature where Celsius and Fahrenheit read exactly the same (-40 °C = -40 °F), because the two scales cross there. Kelvin never goes negative - 0 K is absolute zero (-273.15 °C), the coldest anything can be - so if a Kelvin conversion comes out below zero, the input was physically impossible, which is why this tool flags it. And note Kelvin is written without a degree sign: it's '300 K', not '300 °K'. ## Frequently asked questions ### 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). ## Related tools - [Meters to Feet Converter](https://candoya.com/tools/meters-to-feet/) - [BTU to kW Converter](https://candoya.com/tools/btu-to-kw/) --- *Markdown edition of , published for AI agents and other automated readers. Index of key pages: .*