How To Convert Temperature Units Calculator
Temperature is the one common conversion that is not a simple multiplication. Each scale has its own zero point as well as its own degree size, so every conversion is an affine transformation rather than a ratio.
Converted temperature
212 °F
- Celsius
- 100 °C
- Fahrenheit
- 212 °F
- Kelvin
- 373.15 K
- Rankine
- 671.67 °R
°F = °C × 9/5 + 32 · K = °C + 273.15 · °R = (°C + 273.15) × 9/5
The formula this calculator uses
°F = °C x 9/5 + 32, K = °C + 273.15, °R = (°C + 273.15) x 9/5
- °C
- Degrees Celsius
- °F
- Degrees Fahrenheit
- K
- Kelvin, the SI base unit
- °R
- Degrees Rankine
How to check the result by hand
- 1
Convert the input to Celsius
From Fahrenheit subtract 32 and multiply by five ninths. From kelvin subtract 273.15. From Rankine subtract 491.67 and multiply by five ninths. Celsius is already done.
- 2
Convert Celsius to the target
To Fahrenheit multiply by nine fifths and add 32. To kelvin add 273.15. To Rankine add 273.15 and multiply by nine fifths.
- 3
Check against a fixed point
Water freezes at 0 and 32 and boils at 100 and 212. Body temperature is 37 and 98.6. If the result is nowhere near a known anchor, the offset step was probably skipped.
- 4
Check the sign
Kelvin and Rankine are absolute scales, so a negative result means the input was below absolute zero and something is wrong with the entry.
- 5
Round for the purpose
Whole degrees for weather and cooking, one decimal for most engineering work, and full precision only for laboratory calculations.
For worked examples, common mistakes and the limits of this formula, read the full How To Convert Temperature Units page.