Fahrenheit to Celsius Converter
Convert temperatures between Fahrenheit, Celsius, Kelvin and Rankine — and convert temperature differences the right way.
Method reviewed October 22, 2026. Version 1.0.0. How it works
Result
- °F
- 72°F
- °C
- 22.22°C
72 °F = 22.22 °C.
- K
- 295.4K
- °R
- 531.7°R
Show the working
- °C = (°F − 32) × 5/9(72 − 32) × 5/9 = 22.22 °C
Readings and differences are converted differently
A temperature reading uses the offset between the scales: °C = (°F − 32) × 5 ÷ 9. A temperature difference does not, because the offset cancels: Δ°C = Δ°F × 5 ÷ 9.
This matters constantly in HVAC. A 20 °F temperature split across a coil is an 11.1 K (or °C) difference. Converting it as a reading gives −6.7 °C, which is meaningless. Choose “temperature difference” in the form for splits, rises, superheat, subcooling and design ΔT.
Worked example
These are the example values the calculator opens with, and the result the engine calculates for them.
Inputs
- Value
- 72
- From
- °F Fahrenheit
- This value is
- A temperature reading
Result
- °F
- 72 °F
- °C
- 22.22 °C
- K
- 295.4 K
- °R
- 531.7 °R
72 °F = 22.22 °C.
Assumptions
- Exact definitions: °F = °C × 9/5 + 32; K = °C + 273.15; °R = °F + 459.67.
Frequently asked questions
What is 72 °F in Celsius?
22.2 °C: (72 − 32) × 5 ÷ 9 = 22.22.
When do I use Kelvin or Rankine?
Kelvin and Rankine are absolute scales that start at absolute zero. They appear in gas-law and thermodynamic equations — for example the saturation-pressure equations behind the psychrometric calculators on this site.
Sources
- NIST Guide to the SI (SP 811), Appendix B.9 — conversion factors — National Institute of Standards and Technology. 1 ton of refrigeration = 12,000 BTU/h; 1 BTU/h = 0.2930711 W; 1 atm = 101.325 kPa.
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