Fahrenheit to Celsius Converter

What Is the Fahrenheit to Celsius Converter?

This tool converts a temperature reading in Fahrenheit (°F), the scale used for everyday temperatures in the US, into Celsius (°C), the scale used almost everywhere else in the world and throughout science and medicine. Unlike most unit conversions on this site, temperature conversion isn't a simple multiplication -- Fahrenheit and Celsius don't share a common zero point, so the formula needs both a scale change and an offset.

How to Use This Converter

Enter a Fahrenheit temperature. The result updates instantly, showing the equivalent in Celsius and Kelvin at the same time, so you have all three common temperature scales side by side without converting twice.

The Fahrenheit to Celsius Formula

Fahrenheit sets 32° as water's freezing point and 212° as its boiling point (a 180-degree span), while Celsius sets those same two points at 0° and 100° (a 100-degree span) -- subtracting 32 first removes Fahrenheit's offset, and multiplying by 5/9 (100/180 simplified) rescales the span to match Celsius.

Worked Examples

Common Temperature Reference

Common Mistakes

• Multiplying by 5/9 before subtracting 32 -- order matters, since Fahrenheit's offset (32) must be removed first, before the scale is rescaled.
• Confusing a temperature difference with an absolute temperature -- a 10-degree Fahrenheit change converts to a Celsius change using only the 5/9 scale factor (no offset), which is a genuinely different calculation than converting an absolute reading.

Practical Uses

Reading a US weather forecast in Celsius for an international audience, or vice versa. Following an international recipe that lists oven temperatures in Celsius. Checking a fever reading against a Celsius-based medical reference. For the reverse direction, see the Celsius to Fahrenheit Converter; for scientific work, see the Fahrenheit to Kelvin Converter.

A Worked Example With an Oven Recipe

Suppose a US recipe tells you to bake at 350°F and your oven dial is marked in Celsius. Subtract 32 to get 318, then multiply by 5/9. That gives about 176.7°C. Most Celsius ovens have dials in steps of 5 or 10, so you would choose 175°C or 180°C; the difference is small for most baking, but a very delicate recipe may call for the closer figure. The converter shows the exact decimal so you can decide how to round for your own appliance.

Negative Results and Cold Readings

Fahrenheit values below 32 give negative Celsius values, which is expected. For example, 14°F gives (14 − 32) × 5/9 = −10°C. The sign is easy to lose when doing this by hand, so keep the parentheses around the subtraction. If the input is below 32 the number inside the brackets is negative, and the result must be negative too.

Rounding and Precision

• For weather and cooking, one decimal place is plenty.
• For laboratory or engineering work, carry more digits through the whole calculation and round only at the end.
• Body temperature comparisons benefit from one decimal, since a tenth of a degree can matter when tracking a fever, but any health interpretation belongs with a clinician.

A Quick Mental Estimate

When you only need a rough idea, subtract 30 and halve the result. For 77°F that gives about 23.5°C, whereas the exact answer is 25°C. The shortcut drifts as temperatures get higher, so use the tool whenever accuracy matters.

Frequently Asked Questions