Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin and Rankine instantly.
Convert Celsius, Fahrenheit, Kelvin and Rankine
Temperature scales differ in two ways: where zero sits, and how big a degree is. Celsius puts zero at water’s freezing point, Fahrenheit at a colder reference and uses smaller degrees, while Kelvin starts at absolute zero — the point where molecular motion stops — and uses Celsius-sized degrees.
Because the zero points differ, you cannot simply multiply between them; there is always an offset. This converter shows all four scales at once so the relationship is visible rather than something you have to trust.
Key features
- All four scales simultaneously — change one and the other three update instantly.
- Common reference points — one tap for freezing, room temperature, body heat, boiling and oven settings.
- Absolute zero check — a physically impossible temperature is flagged rather than silently converted.
- Two-decimal precision — enough for cooking, weather and laboratory work alike.
This tool does its work inside your browser using native Web APIs. The files and text you give it are processed on your device and are not uploaded to our servers.
How to use: Temperature Converter
- Enter a temperature
Type the number into the value field. - Select the scale it is in
Celsius, Fahrenheit, Kelvin or Rankine. - Read all four results
Every scale updates at once, so no second conversion is needed. - Use a preset for a quick check
The reference buttons jump straight to well-known points like body temperature or a 180 °C oven.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Converters |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. So 20 °C × 1.8 = 36, plus 32 = 68 °F. To reverse it, subtract 32 first and then multiply by 5/9 — the order matters.
At what temperature are Celsius and Fahrenheit equal?
At −40. That is the single crossing point of the two scales, which is why −40 °C and −40 °F are the same temperature and why the figure appears so often in cold-weather specifications.
What is absolute zero?
0 kelvin, equal to −273.15 °C or −459.67 °F. It is the theoretical point at which particles have minimum energy. Nothing can be colder, so any input implying a negative kelvin value is flagged as impossible.
What is Rankine used for?
Rankine is an absolute scale using Fahrenheit-sized degrees, still used in some US engineering and thermodynamics work — particularly aerospace and HVAC — where an absolute scale is needed but imperial units are the convention.