Weather
The gap between the scales is widest in the range people care about. 20 °C is a pleasant 68 °F, 30 °C is a hot 86 °F, and 35 °C is 95 °F — the point where heat advisories start in both systems.
Temperature
Convert fahrenheit to celsius
1 fahrenheit equals -17.222222 celsius. Enter a value below to convert instantly.
Fahrenheit to Celsius reverses the offset before the ratio: subtract 32 first, then multiply by 5/9. Getting that order wrong is the single most common error in temperature conversion, and it produces answers that look plausible — which is what makes it dangerous.
Need the other direction? Convert celsius to fahrenheit →
Formula
°C = (°F − 32) × 5/9
Not a simple multiplication. These scales have different zero points, so the conversion applies an offset as well as a ratio.
Step by step
- Start with 1 °F.
- Apply the Fahrenheit-to-Celsius formula.
- The result is -17.222222 °C.
Fahrenheit to Celsius conversion table
| Fahrenheit (°F) | Celsius (°C) |
|---|---|
| -40 | -40 |
| -20 | -28.888889 |
| 0 | -17.777778 |
| 10 | -12.222222 |
| 20 | -6.6666667 |
| 32 | 0 |
| 37 | 2.7777778 |
| 50 | 10 |
| 98.6 | 37 |
| 100 | 37.777778 |
Where fahrenheit and celsius are used together
Oven temperatures
Recipes cross borders constantly and ovens do not. 180 °C is 356 °F, which US recipes round to 350 °F; 200 °C is 392 °F, rounded to 400 °F. Those roundings are why a converted baking time sometimes needs a few minutes' adjustment.
Body temperature
Normal body temperature is about 37 °C or 98.6 °F, and the fever threshold usually quoted is 38 °C or 100.4 °F. The 98.6 figure is itself a conversion artefact — it is 37 °C converted to one decimal place, which implies far more precision than the original measurement had.
Refrigeration and freezing
A fridge should sit at or below 4 °C (39 °F) and a freezer at −18 °C (0 °F). The freezer figure is a good example of a round number in one scale converting to a round number in the other, which is why both are quoted as standards.
Everyday fahrenheit worth knowing
Values people actually look up, with the reason each one comes up. Every figure is calculated with the same engine as the converter above.
| Fahrenheit (°F) | Celsius (°C) | What it is |
|---|---|---|
| -40 | -40 | Where the two scales meet |
| 0 | -17.777778 | Standard freezer temperature |
| 32 | 0 | Water freezes |
| 68 | 20 | Room temperature |
| 98.6 | 37 | Normal body temperature |
| 100.4 | 38 | A commonly cited fever threshold |
| 212 | 100 | Water boils at sea level |
| 350 | 176.66667 | A common US baking temperature |
How these two units are defined
Celsius places 0 at the freezing point of water and 100 at its boiling point at standard pressure. Fahrenheit places those same two points at 32 and 212, so 180 Fahrenheit degrees span the same interval as 100 Celsius degrees — a Fahrenheit degree is 5/9 the size of a Celsius one. Both are now formally defined against the kelvin: the Celsius scale is exactly the kelvin scale shifted by 273.15, and Fahrenheit is defined from Celsius. The two scales cross at −40, where both read the same number.
Rounding and precision
Because a Fahrenheit degree is smaller, a converted Celsius value gains apparent precision it does not have: 20 °C measured to the nearest degree becomes 68 °F, but the true value could be anywhere from 66.2 to 69.8 °F. Round converted temperatures back to a sensible precision — whole degrees for weather, one decimal for clinical readings, and the nearest 5 or 10 for ovens, which cannot hold better than that anyway.
Mistakes people make with this conversion
-
Adding 32 before multiplying
Going from Fahrenheit to Celsius, subtract 32 first. Doing it the other way turns 100 °F into 73.3 °C instead of 37.8 °C — an answer that is wrong by enough to matter and not obviously absurd.
-
Converting a temperature difference like a temperature
A 10 °C rise is an 18 °F rise, not 50 °F. Differences use only the 9/5 ratio, with no offset. The site has a separate temperature-interval converter for exactly this.
-
Trusting 98.6 °F as a precise normal
It is 37 °C converted to one decimal place. The underlying figure was never that precise, and normal body temperature varies by person and time of day.
Read more about these units
Sources for this page
- SI Brochure — The International System of Units (SI), 9th edition
- Special Publication 330 — The International System of Units (SI), 2019 Edition
Content on this page last reviewed 12 August 2026. Spotted an error? Report it — see also how these values are calculated.
Convert Fahrenheit to other temperature units
1 °F expressed in every other temperature unit on this site.
About the fahrenheit
The fahrenheit (°F) is a US unit of temperature.
About the celsius
The celsius (°C) is a Metric unit of temperature.
Related conversions
Frequently asked questions
What is the formula for Fahrenheit to Celsius?
°C = (°F − 32) × 5/9. Subtract the offset first, then apply the ratio — reversing the order is the most common mistake in temperature conversion.
What is 350 °F in Celsius?
350 °F is 176.7 °C, which recipes and oven dials round to 175 °C or 180 °C. That rounding is why converted baking temperatures often come with a note to watch the first bake.
What is a fever in Celsius?
The commonly cited threshold of 100.4 °F is exactly 38 °C — the Fahrenheit figure is the converted one, which is why it has an odd decimal. Clinical guidance on what counts as a fever varies by age and context and should come from a medical source.
How many celsius are in a fahrenheit?
One fahrenheit equals -17.222222 celsius.
How do you convert fahrenheit to celsius?
°C = (°F − 32) × 5/9
What is 1 celsius in fahrenheit?
One celsius equals 33.8 fahrenheit.
When would I convert fahrenheit to celsius?
This conversion is common when cooking, weather, medical readings, and science experiments.