Quick Answer: Fahrenheit to Celsius
0 °F is approximately -17.78 °C, and 1 °F is approximately -17.22 °C (°C = (°F − 32) × 5/9).
Conversely, 1 °C = 33.8 °F.
Formula: °C = (°F − 32) × 5/9
Worked examples
- 0 °F ≈ -17.78 °C
- 32 °F = 0 °C
- 50 °F = 10 °C
Method and limitations
Subtract 32, then multiply by 5/9: °C = (°F − 32) × 5/9. This converts a temperature reading. A temperature difference converts without the offset: Δ°C = Δ°F × 5/9. Calculations use full-precision constants; answers in this box are rounded for readability (≈ marks a rounded value) and the calculator shows up to 9 significant figures. Temperature scales use an offset, not a single multiplier, so this converts a temperature reading. A temperature difference (for example a 10-degree rise) converts with the scale factor only, without the offset.
Each factor is exact by definition, derived from exact definitions, or a documented conventional value — see the methodology and sources.
Conversion Formula
Subtract 32, then multiply by 5/9: °C = (°F − 32) × 5/9. This converts a temperature reading. A temperature difference converts without the offset: Δ°C = Δ°F × 5/9.
Complete Guide to Fahrenheit to Celsius Conversion
What is the Fahrenheit scale?
On the Fahrenheit scale water freezes at 32 °F and boils at 212 °F at standard atmospheric pressure, so there are 180 Fahrenheit degrees between those points.
What is the Celsius scale?
On the Celsius scale the same points are 0 °C and 100 °C. Since 2019 the Celsius scale is defined from the kelvin: °C = K − 273.15.
How the Conversion Works
The 180 °F span maps onto 100 °C, so one Fahrenheit degree is 5/9 of a Celsius degree. Subtracting 32 first aligns the freezing points. The two scales read the same at −40.
Step-by-Step Conversion Guide
Follow these steps to convert fahrenheit to celsius manually:
Start with your value in fahrenheit
Example: You want to convert 50 °F
Apply the conversion formula
Use the formula: °C = (°F − 32) × 5/9
Calculate the result
50 °F = 10 °C
Verify your answer
Use our calculator above to double-check your manual calculation.
Quick Mental Math Tip
Subtract 30 and halve for a rough figure: 70 °F ≈ 20 °C (exact 21.1). It drifts at oven temperatures, so use the exact formula there.
Common Conversions
| Fahrenheit (°F) | Celsius (°C) | Celsius → Fahrenheit |
|---|---|---|
| 0 °F | -17.7778 | 0 °C = 32 °F |
| 32 °F | 0 | 32 °C = 89.6 °F |
| 50 °F | 10 | 50 °C = 122 °F |
| 68 °F | 20 | 68 °C = 154.4 °F |
| 77 °F | 25 | 77 °C = 170.6 °F |
| 86 °F | 30 | 86 °C = 186.8 °F |
| 98.6 °F | 37 | 98.6 °C = 209.48 °F |
| 100 °F | 37.7778 | 100 °C = 212 °F |
| 212 °F | 100 | 212 °C = 413.6 °F |
| 350 °F | 176.667 | 350 °C = 662 °F |
| 400 °F | 204.444 | 400 °C = 752 °F |
| 450 °F | 232.222 | 450 °C = 842 °F |
Popular Fahrenheit to Celsius Conversions
Tap any value to load it into the calculator above.
When You'll Need This Conversion
US oven settings
Turn a US recipe temperature such as 375 °F (190.56 °C) into a setting for a Celsius oven.
US weather forecasts
Read a forecast high of 95 °F as 35 °C.
Thermostats
Translate a 68 °F thermostat setting (20 °C) for a Celsius controller.
Pro Tips for Accurate Conversions
Readings vs differences
A forecast "10 °F warmer than yesterday" is a 5.56 °C difference, not −12.2 °C.
Common Mistakes to Avoid
Multiplying before subtracting 32
68 × 5/9 − 32 gives 5.8, not 20.
(68 − 32) × 5/9 = 20 °C.
Using the reading formula on a difference
The 32 offset belongs to readings only.
Δ°C = Δ°F × 5/9.
Frequently Asked Questions
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Conversion factors on this page are either exact by definition, derived from exact definitions, or conventional values in documented use. Each is listed with its source in our conversion methodology and sources, which cites the BIPM SI Brochure, NIST Special Publication 811 and the relevant IEC or national standards. Results are rounded for display only; calculations use full precision.