About Temperature Converter
Temperature Converter translates a temperature between the three scales you are likely to meet: Celsius, Fahrenheit and Kelvin. Enter the figure, say which scale it is on, say which scale you want, and it returns the converted value.
Unlike every other converter in this category, temperature is not a simple multiplication, because the scales have different zero points. The conversion therefore goes through Celsius as an intermediate: Fahrenheit values are shifted by 32 and scaled by five ninths, and Kelvin values are offset by 273.15 from Celsius. That offset is why 0 °C is 32 °F but 100 °C is 212 °F, a range of 180 Fahrenheit degrees rather than 100 — an interval of one Celsius degree equals 1.8 Fahrenheit degrees.
That ratio leads to the one real trap with this tool. It converts temperature points, not temperature differences. If you want to know how much a rise of 10 °C is in Fahrenheit, the answer is 18 °F, but entering 10 here gives 50 °F, because the tool treats the input as an absolute temperature. For interval questions, scale the number by 1.8 yourself instead of using the converter.
How to use Temperature Converter
- 1 Enter the temperature to convert.
- 2 Choose the scale it is measured in — Celsius, Fahrenheit or Kelvin.
- 3 Choose the scale you want and run the tool.
Frequently asked questions
Can I use this to convert a temperature difference?
No, and this is the most common mistake. The tool converts absolute temperatures, so a rise of 10 °C entered directly gives 50 °F rather than the correct 18 °F. For differences, multiply or divide by 1.8 instead of shifting through the zero points.
Why is 0 °C not 0 °F?
Because the scales have different zero points. Fahrenheit places its zero at the freezing point of a brine mixture, so water freezes at 32 °F. Celsius places its zero at the freezing point of water. Converting between them requires both a scale factor and an offset.
Is Kelvin ever negative?
Not physically. Kelvin starts at absolute zero, with no negative values in nature, so a negative Kelvin input represents something outside the physical world. The arithmetic still runs, but the result has no physical meaning.
What is the conversion between Celsius and Fahrenheit?
Multiply by nine fifths and add 32. So 25 °C becomes 25 times 1.8 plus 32, which is 77 °F. The reverse subtracts 32 first and then multiplies by five ninths. The tool applies exactly this, using Celsius as its intermediate scale.
Free, online, and private
Free to use
Temperature Converter is completely free. There is no account to create, no login, and no hidden charge or usage limit.
Runs online in your browser
It is a free online tool that runs entirely in your browser. Nothing to download or install — open the page and start using it right away.
Your data stays private
All processing happens locally on your device. Your input is never uploaded, stored, or tracked, so it never leaves your browser.
How Temperature Converter behaves in detail
These are the specifics of this implementation — the exact ranges, defaults and fixed settings you are working with.
| Parameter | Value |
|---|---|
| Units covered | 3 — Celsius, Fahrenheit and Kelvin |
| Method | offset formulas rather than one shared multiplier — the only converter in this set that is not a plain ratio |
| Formulas | °F = °C × 9/5 + 32 · K = °C + 273.15, with the reverse forms used on the way back |
| Result precision | none — the raw double is printed, so 0 °C returns exactly 32 and 37 °C returns exactly 98.6 |
| Form artefact | all three units carry a factor of 1 because the offsets live in the run function, not in the unit table |
| Default pair | C → F |
Compiled from the implementation of this tool and checked against it by itoolnet.
What Temperature Converter does not do
Knowing the edges of a tool saves more time than another list of its features. These are the cases where it will not do what you might expect.
- This converts absolute temperatures, not temperature intervals. A rise of 10 degrees is 10 °C but 18 °F, and running a delta through this page adds the 32-degree offset as well — Temperature Difference Converter is the tool built for gaps.
- The result is never rounded. The raw double is turned into a string, so inputs that are not exactly representable print every digit: 200 °F comes back as 93.33333333333334, 36.6 °C as 97.88000000000001, and −48 °C as −54.400000000000006.
- Only the three major scales are here. Rankine and gas mark are separate tools, and each run returns a bare number — neither the value you typed nor the conversion route is echoed, so there is no side-by-side view of the scales to check the arithmetic against.
Tested and documented by itoolnet, the team that builds and maintains this site.