Fahrenheit to Celsius Converter
Convert a temperature between Fahrenheit, Celsius, and Kelvin. Enter a Fahrenheit value and the tool shows the matching Celsius and Kelvin readings, using the standard definitions °C = (°F − 32) × 5/9 and K = °C + 273.15. It is useful for reading recipes and oven settings, weather forecasts from another country, lab and science work, and any time a thermostat or thermometer uses the scale you are not used to.
Calculate
Default result: 37.00
Fahrenheit to Celsius Converter · Result
calculators.dev
Celsius (°C)
98.6
- Kelvin (K)
- 310.15
Reviewed by the calculators.dev team · Last updated 2026-06-23
How to calculate
Type a temperature in Fahrenheit and read the Celsius and Kelvin results below. To go the other way by hand, use °F = °C × 9/5 + 32: a 20 °C room is 20 × 9/5 + 32 = 68 °F. A quick mental estimate for °C is to subtract 30 from the Fahrenheit value and halve it, which is close but not exact. The result updates live as you type.
°C = (°F − 32) × 5/9 converts Fahrenheit to Celsius, and °F = °C × 9/5 + 32 reverses it. Kelvin shifts Celsius by a fixed offset: K = °C + 273.15. Unlike a simple ratio, these scales also have an offset, which is why 0 °C is 32 °F rather than 0 °F — the −40 point is the one place the Celsius and Fahrenheit numbers match.
Example calculation
98.6 °F is normal human body temperature. In Celsius that is (98.6 − 32) × 5/9 = 37 °C, and in Kelvin it is 37 + 273.15 = 310.15 K.
- celsius
- 37 °C
- kelvin
- 310.15 K
Assumptions
- The conversions use the modern definitions: the Fahrenheit-to-Celsius relationship is exact, and Kelvin is Celsius plus exactly 273.15.
- Absolute zero (0 K, or −273.15 °C) is the lowest possible temperature; values below it are rejected because they are physically impossible.
- Results are shown rounded for readability while the underlying calculation keeps full precision.
Common mistakes
- Forgetting the +32 offset and treating the conversion as a plain ratio — Celsius and Fahrenheit do not share a zero point, so you must add or subtract 32.
- Multiplying by 9/5 when converting Fahrenheit to Celsius instead of multiplying by 5/9 after subtracting 32.
- Confusing Kelvin with Celsius: Kelvin has no degree symbol and starts at absolute zero, so 0 °C is 273.15 K, not 0 K.
Frequently asked questions
What is 100 °C in Fahrenheit?
100 °C is 212 °F, the boiling point of water at sea level (100 × 9/5 + 32 = 212).
How do I convert Fahrenheit to Celsius by hand?
Subtract 32, then multiply by 5/9: °C = (°F − 32) × 5/9. For example, 68 °F is (68 − 32) × 5/9 = 20 °C.
At what temperature do Celsius and Fahrenheit read the same?
At −40 degrees. −40 °C equals −40 °F, the single point where the two scales cross.
How is Kelvin related to Celsius?
Kelvin uses the same size degree as Celsius but starts at absolute zero, so K = °C + 273.15. Water freezes at 273.15 K and boils at 373.15 K.