How to Convert Fahrenheit to Celsius (Weather and Oven Temperatures)
To convert Fahrenheit to Celsius, subtract 32, then multiply by 5/9. So 68°F becomes (68 − 32) × 5/9 = 20°C. The order matters: subtract first, multiply second. Get that backward and every result is wrong, and it’s especially easy to get backward when the number you’re converting is a recipe’s oven temperature, where a few degrees actually changes how something bakes.
The formula
C = (F − 32) × 5/9Subtract 32 from the Fahrenheit reading first, then multiply what’s left by 5/9 (or divide by 1.8, same thing). Reversed, going Celsius to Fahrenheit, you multiply by 9/5 and add 32 last.
The 32 exists because the two scales don’t share a zero point. Fahrenheit puts freezing at 32 and boiling at 212, a 180-degree span. Celsius puts the same two events at 0 and 100, a 100-degree span. Divide 100 by 180 and you get 5/9, the ratio that rescales one span onto the other. Once you subtract 32, you’ve lined up the zero points; the multiplication then just rescales the size of a degree.
Everyday reference points
| Fahrenheit | Celsius | Context |
|---|---|---|
| -40°F | -40°C | The one point where both scales agree |
| 0°F | -17.8°C | A brutal cold snap |
| 32°F | 0°C | Water freezes |
| 50°F | 10°C | Cool spring day |
| 68°F | 20°C | Comfortable room temperature |
| 72°F | 22.2°C | A typical thermostat setting |
| 98.6°F | 37°C | Normal human body temperature |
| 100.4°F | 38°C | Low-grade fever |
| 212°F | 100°C | Water boils |
Take 72°F: (72 − 32) × 5/9 = 40 × 5/9 = 22.2°C. Or check 100.4°F: (100.4 − 32) × 5/9 = 68.4 × 5/9 = 38°C, a reading that shows up constantly when a friend abroad texts you a fever in Fahrenheit and you need to know if it’s serious.
Recipe oven temperatures: the numbers that actually matter
This is where the conversion stops being trivia and starts affecting your dinner. American recipes list oven temperatures in Fahrenheit; most of the world’s ovens are dialed in Celsius. Rounding carelessly here changes bake time and browning, so these are worth having exact:
| Recipe (°F) | Celsius | Typical use |
|---|---|---|
| 325°F | 163°C | Slow roasting, low-and-slow bakes |
| 350°F | 177°C | Standard baking temperature |
| 375°F | 191°C | Most cookies |
| 400°F | 204°C | Roasting vegetables, sheet-pan meals |
| 425°F | 218°C | Pizza, high-heat roasting |
| 450°F | 232°C | Broiling, very hot bakes |
Most ovens only have dial marks every 10 or 25 degrees, so you’ll often round the exact figure to the nearest setting your oven actually offers, 177°C becomes 175°C or 180°C depending on the dial. That’s fine. What’s not fine is rounding the Fahrenheit number itself before converting, treating 350°F as “close enough to 300” because the recipe felt long. Convert the number as written, then round the result to your oven’s nearest mark, not the other way around.
Convert with your own numbers
Enter any Fahrenheit reading below to get the exact Celsius value, or flip it to go the other direction.
Common mistakes
Multiplying before subtracting 32. The formula only works in the order C = (F − 32) × 5/9. Multiply first and you’ll get a number that looks plausible but is off by a wide margin. 68°F done wrong as 68 × 5/9 − 32 gives roughly 5.8°C instead of the correct 20°C.
Using a mental shortcut on a number that needs to be exact. A quick trick for casual conversation is to subtract 30 and divide by 2. It happens to be exact right at 50°F (10°C) and stays close nearby, but it drifts the further you move from there:
| Fahrenheit | Shortcut (−30, ÷2) | Actual | Error |
|---|---|---|---|
| 0°F | -15°C | -17.8°C | 2.8°C |
| 32°F | 1°C | 0°C | 1°C |
| 50°F | 10°C | 10°C | 0°C |
| 70°F | 20°C | 21.1°C | 1.1°C |
| 98.6°F | 34.3°C | 37°C | 2.7°C |
Good enough for guessing whether you need a jacket. Not good enough for a recipe or a fever reading, where 2 to 3 degrees is a real difference.
Converting a temperature change the same way as a temperature reading. If a recipe says to run the oven 25°F hotter than the base setting, that 25°F is a gap, not a point on the thermometer, and gaps convert differently. For a difference, only the 5/9 (or ÷1.8) part applies, the −32 gets left out entirely, since it’s an offset anchored to each scale’s zero point, and a gap has no zero point of its own. A 25°F increase is a 13.9°C increase (25 ÷ 1.8), not the result you’d get from running the full formula on 25.
Frequently asked questions
What is 350°F in Celsius? 350°F = 177°C, the most common American baking temperature.
What is 98.6°F in Celsius? 98.6°F = 37°C, normal human body temperature.
What is 0°F in Celsius? 0°F = -17.8°C, an extreme cold reading.
How do I convert an American recipe’s oven temperature exactly? Apply the formula to the number as printed, C = (F − 32) × 5/9, then round the result to the nearest setting your oven’s dial actually offers. Don’t round the Fahrenheit figure first.
Is there a fast way to estimate Fahrenheit to Celsius in my head? Subtract 30 and divide by 2. It’s exact at 50°F and stays within a couple of degrees nearby, but drifts further out the more extreme the temperature, so use the real formula for anything that needs to be precise.
Is there a temperature where Fahrenheit and Celsius read the same number? Yes, -40. Both -40°F and -40°C describe the same temperature, the single point where the two scales cross.