Temperature Converter — Celsius, Fahrenheit, Kelvin, Rankine
Type a value in any field and every other temperature scale updates instantly. Covers all four major scales — Celsius, Fahrenheit, Kelvin, and Rankine.
| Reference | °C | °F | K | °R |
|---|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 | 0 |
| Water Freezes | 0 | 32 | 273.15 | 491.67 |
| Human Body | 37 | 98.6 | 310.15 | 558.27 |
| Water Boils | 100 | 212 | 373.15 | 671.67 |
| Oven (hot) | 230 | 446 | 503.15 | 905.67 |
How to use this tool
- 1Find the scale you know
Locate the input field for the temperature scale you have — for example, Celsius (°C) or Fahrenheit (°F). Or use a quick-preset button for common reference points.
- 2Type the value
Enter your number into the field. All other temperature scales update instantly as you type — no button click needed.
- 3Copy the result
Click the copy button next to any converted value to copy it to your clipboard. Use Clear All to reset everything.
A brief history of temperature scales
Celsius and Fahrenheit
Anders Celsius proposed his scale in 1742, originally with 0 as the boiling point and 100 as freezing. It was soon inverted to the familiar form: 0 °C for freezing, 100 °C for boiling. Daniel Fahrenheit developed his scale in 1724, setting 32 °F as the freezing point and 212 °F as the boiling point of water. The US and a handful of territories still use Fahrenheit day-to-day.
Kelvin — the SI unit
Lord Kelvin proposed an absolute temperature scale in 1848, starting at absolute zero (−273.15 °C). One kelvin increment equals one degree Celsius. Kelvin is the SI base unit of temperature and is used universally in science. In 2019, the kelvin was redefined in terms of the Boltzmann constant rather than the triple point of water.
Rankine in engineering
The Rankine scale, proposed by William John Macquorn Rankine in 1859, is the Fahrenheit-based absolute scale. Like Kelvin, it starts at absolute zero but uses Fahrenheit-sized degrees. It is still used in some branches of US engineering, particularly in thermodynamic calculations for HVAC and combustion systems.
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