Temperature Converter

Convert Fahrenheit to Celsius, Celsius to Fahrenheit, and either to Kelvin or Rankine.

Decimals, fractions (3 1/2) and e-notation (1.5e6) all work.
Common Conversions
Significant Digits
Result
Formula
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Exact?

In Every Unit

UnitValue

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How to Convert Temperature Units

Temperature scales have different zero points, so converting takes a multiply and an add, not just a factor. A Celsius degree is 1.8 times the size of a Fahrenheit degree, and water freezes at 0 °C and 32 °F.

°F = °C × 9/5 + 32   °C = (°F − 32) × 5/9
K = °C + 273.15   °R = °F + 459.67

Worked Example

Common Conversions

FromEquals
32 °F0 °C
212 °F100 °C
0 °C32 °F
100 °C212 °F
0 °C273.15 K
100 °C373.15 K
300 K26.85 °C
32 °F273.15 K
212 °F373.15 K
32 °F491.67 °R
212 °F671.67 °R

Unit Definitions

UnitEqualsExact?
CelsiusK − 273.15Exact
Fahrenheit°R − 459.67, degree = 5/9 KExact
KelvinSI base unitExact
RankineK × 9/5Exact

Factors follow NIST Special Publication 811, Appendix B. "Exact" means the unit is defined as that value; results are rounded only for display.

Tips

A quick mental check: double the Celsius temperature and add 30 to get roughly Fahrenheit. −40 is the same in both scales. For a temperature difference (a rise of 10 degrees), multiply or divide by 1.8 only; don't add or subtract 32.