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Fahrenheit to Celsius Calculator.

Converts a temperature from Fahrenheit to Celsius and also shows the Kelvin equivalent.

Results update live as you type.
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Your inputs

How it works

  1. 1

    Subtract 32 from the Fahrenheit value.

  2. 2

    Multiply the result by 5.

  3. 3

    Divide by 9 to get Celsius.

  4. 4

    For Kelvin, add 273.15 to the Celsius result.

(fahrenheit - 32) * 5 / 9

Frequently asked questions

What is the formula to convert Fahrenheit to Celsius?

Subtract 32 from the Fahrenheit temperature, then multiply by 5/9. For example, 68°F becomes (68-32)*5/9 = 20°C.

Why is -40 the same in both scales?

Because the conversion formula yields -40 when you plug in -40: (-40-32)*5/9 = -40. The scales intersect at that point.

How do I convert Celsius back to Fahrenheit?

Multiply the Celsius temperature by 9/5 and add 32. For instance, 20°C becomes 20*9/5+32 = 68°F.

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Celsius

0°C

Kelvin0K
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Estimate for general guidance only — verify important decisions with an appropriate professional.

How it works

Converts a temperature from Fahrenheit to Celsius and also shows the Kelvin equivalent.

  1. Subtract 32 from the Fahrenheit value.
  2. Multiply the result by 5.
  3. Divide by 9 to get Celsius.
  4. For Kelvin, add 273.15 to the Celsius result.

Formulas

The math behind this calculator, written out so you can verify the result.

Fahrenheit to Celsius

°C = (°F - 32) × 5/9

This linear conversion adjusts for the different zero points and scale sizes of the two temperature scales.

Example:

Input: °F = 77

Calculation: (77 - 32) × 5/9

Result: 25°C

Fahrenheit to Kelvin

K = (°F - 32) × 5/9 + 273.15

Kelvin is an absolute temperature scale, so you first convert to Celsius and then add 273.15.

Example:

Input: °F = 32

Calculation: (32 - 32) × 5/9 + 273.15

Result: 273.15 K

Real-world use cases

Where this calculation shows up in everyday life.

Cooking and Baking

Many recipes use Fahrenheit, but ovens in other countries are marked in Celsius. Convert to set the right temperature.

Example: 350°F becomes 176.67°C.

Weather and Travel

When traveling to a country that uses Celsius, quickly understand the local temperature in familiar terms.

Example: A forecast of 86°F is 30°C.

Science and Education

Students and professionals often need to convert temperatures for experiments or data analysis.

Example: Body temperature 98.6°F is 37°C.

Tips and common mistakes

Tips

  • Remember the freezing point of water: 32°F = 0°C.
  • A quick mental estimate: subtract 30 and halve the result for a rough Celsius value.
  • For precise conversions, always use the exact formula with 5/9.
  • Check your result: 100°C (boiling) should be 212°F.

Common Mistakes to Avoid

  • Forgetting to subtract 32 before multiplying.
  • Using 9/5 instead of 5/9 when converting to Celsius.
  • Rounding too early in multi-step calculations.

Assumptions and limitations

  • Use the stated inputs and units.
  • Results are estimates for planning and education.
  • Check measurements and source data before making an important decision.