Fahrenheit to Celsius Converter (°F to °C)

Fahrenheit to Celsius formula

To change °F into °C, subtract 32 and then multiply by 5/9:

°C = (°F − 32) × 5/9

The brackets are important. You remove the 32-degree offset first, because Fahrenheit starts counting from a point 32 degrees below the freezing point of water. Only after that do you scale the number down, since a Fahrenheit degree is smaller than a Celsius degree (5/9 of the size).

Example with 350 °F: 350 − 32 = 318. Then 318 × 5 = 1590, and 1590 ÷ 9 = 176.67. So 350 °F is 176.67 °C, which recipes usually round to 180 °C. Multiplying by 5/9 is the same as dividing by 1.8, so (350 − 32) ÷ 1.8 gives the same answer on a phone calculator.

Worked examples

Each row below uses the same two steps. Notice how the oven temperatures land on awkward decimals — that is why European recipes round them to the nearest 5 or 10 degrees.

Cooking with a fan oven? Recipes written in Fahrenheit almost always assume a conventional oven, so a fan oven usually needs about 20 °C less. The oven conversion page has a ready-made table with gas marks.

Fahrenheit to Celsius chart (0–220 °F)

This range covers winter weather, room temperature, hot drinks and boiling water. Every 10 °F step is about 5.56 °C.

Key points to remember

• 0 °F = −17.78 °C — a very cold day; Fahrenheit's zero is well below freezing.
• 32 °F = 0 °C — water freezes.
• 50 °F = 10 °C — a cool spring morning.
• 68 °F = 20 °C — a typical comfortable room.
• 98.6 °F = 37 °C — a useful conversion reference.
• 212 °F = 100 °C — water boils at sea level.

For values above 220 °F or below zero, use the full Fahrenheit and Celsius charts, which run from −50 °F to 450 °F.

Mental shortcut: subtract 30 and halve

To estimate Celsius in your head, take the Fahrenheit number, subtract 30 and divide by 2. For 80 °F: 80 − 30 = 50, half of 50 is 25, so roughly 25 °C (the exact answer is 26.67 °C).

This is the reverse of the “double it and add 30” rule on our Celsius to Fahrenheit converter. It is close for spring and summer weather and gets less accurate at the extremes, as the table shows.

Want more precision without a calculator? Subtract 32, halve the result, then add a tenth of that half. For 80 °F: 48 ÷ 2 = 24, plus 2.4 gives 26.4 °C — within a third of a degree.

Common mistakes

• Multiplying before subtracting. 350 × 5/9 − 32 gives 162.4, which is wrong. Subtract 32 first.
• Using 9/5 instead of 5/9. Use 5/9 because one Fahrenheit degree is 5/9 of a Celsius degree. Above −40, the Celsius number is smaller; at −40 the numbers match, and below −40 the Celsius number is less negative.
• Converting a difference with the full formula. If a recipe says “reduce the heat by 25 °F”, that is a drop of 25 × 5/9 ≈ 13.89 °C. Do not subtract 32 for a change in temperature.