How to Convert Fahrenheit to Celsius

5 min read•June 1, 2025•Reviewed: June 1, 2026

✓Reviewed by Apex Conversion Editorial Team · Last reviewed June 1, 2026

To convert Fahrenheit to Celsius: subtract 32, then multiply by 5/9 (which is 0.5556). The subtraction removes the offset between the scales' zero points; the multiplication adjusts for the different degree sizes. This covers every practical case from outdoor weather to oven temperatures.

For a quick mental estimate: subtract 30, then halve. For 80°F: (80 − 30) ÷ 2 = 25°C (actual: 26.7°C). This works well for the 40°F–100°F outdoor temperature range and is accurate enough for most travel purposes.

The Formula

°C = (°F − 32) × 5/9
   = (°F − 32) × 0.5556

Worked examples:
  32°F: (32 − 32) × 5/9 =   0°C  (freezing)
  68°F: (68 − 32) × 5/9 =  20°C  (room temperature)
  98.6°F: (98.6 − 32) × 5/9 = 37°C (body temperature)
 212°F: (212 − 32) × 5/9 = 100°C (boiling)

Mental shortcut: (F − 30) ÷ 2
  70°F → (70 − 30) ÷ 2 = 20°C  (actual: 21.1°C)
  50°F → (50 − 30) ÷ 2 = 10°C  (actual: 10.0°C)

Fahrenheit to Celsius Reference Table

°F    °C       °F    °C
────  ─────    ────  ─────
 −40  −40       68   20.0
  14  −10       77   25.0
  32    0       86   30.0
  41    5       95   35.0
  50   10      98.6  37.0
  59   15      104   40.0
  60   15.6    212  100.0
  64   17.8    350  176.7
  68   20      400  204.4

Step-by-Step Method

Step 1 — Subtract 32 from the Fahrenheit temperature. This removes the scale offset. For 75°F: 75 − 32 = 43. Step 2 — Multiply the result by 5/9 (or 0.5556). 43 × 5/9 = 23.9°C. That is the answer.

Why divide by 1.8 instead? Multiplying by 5/9 and dividing by 1.8 are the same operation: 5/9 = 0.5556 and 1/1.8 = 0.5556. Use whichever is faster on your calculator. On most phones, typing (75 − 32) × 5 ÷ 9 is straightforward.

Common Practical Conversions

Weather: 32°F (0°C) is freezing. 50°F (10°C) is cool. 68°F (20°C) is comfortable. 86°F (30°C) is hot. 104°F (40°C) is dangerously hot and uncommon in most climates.

Oven temperatures: American recipes specify Fahrenheit. 325°F = 163°C (slow bake). 350°F = 177°C (standard). 375°F = 190°C. 400°F = 204°C. 425°F = 218°C (hot). These conversions appear in most cookbooks — no need to calculate every time.

Quick Tips

✓
Memorize: 32°F=0°C, 68°F=20°C, 98.6°F=37°C, 212°F=100°C.
✓
Oven temperatures from US recipes: (F − 32) × 5/9. Or use the chart above — oven values repeat.
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For weather: 60°F is cool (15.6°C), 75°F is comfortable (23.9°C), 90°F is hot (32.2°C).
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Body temperature: 98.6°F is normal. A fever is above 100.4°F (38°C).

Frequently Asked Questions

What is 72°F in Celsius?

(72 − 32) × 5/9 = 40 × 5/9 = 22.2°C. A comfortable room temperature.

What is 350°F in Celsius?

(350 − 32) × 5/9 = 318 × 5/9 = 176.7°C. The standard baking temperature in most cake and cookie recipes.

What is 100°F in Celsius?

(100 − 32) × 5/9 = 68 × 5/9 = 37.8°C — above normal body temperature, indicating a slight fever.

Why does the formula subtract 32 first?

Because the two scales have different zero points. Fahrenheit's zero is colder than Celsius zero: 0°F = −17.8°C. Subtracting 32 from Fahrenheit aligns both scales at water's freezing point (0°C = 32°F) before applying the degree-size correction.

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