The Formula
To convert any Celsius temperature to Fahrenheit:
°F = (°C × 9/5) + 32Also written as: °F = (°C × 1.8) + 32 — both are identical.
Step-by-step example — converting 25°C:
- 25 × 9 = 225
- 225 ÷ 5 = 45
- 45 + 32 = 77°F
Step-by-step example — converting 37°C (body temperature):
- 37 × 9 = 333
- 333 ÷ 5 = 66.6
- 66.6 + 32 = 98.6°F
Celsius to Fahrenheit Chart — 19 Common Temperatures
The most frequently needed conversions — from extreme cold through body temperature, fever levels, and oven temperatures:
| °C | °F | What it means |
|---|---|---|
| -40°C | -40°F | Celsius = Fahrenheit (only point) |
| -20°C | -4°F | Very cold winter |
| -10°C | 14°F | Freezing cold |
| 0°C | 32°F | Freezing point of water |
| 10°C | 50°F | Cool autumn day |
| 15°C | 59°F | Mild spring day |
| 20°C | 68°F | Comfortable room temperature |
| 25°C | 77°F | Warm summer day |
| 30°C | 86°F | Hot day |
| 35°C | 95°F | Very hot / heat warning |
| 37°C | 98.6°F | Normal human body temperature |
| 38°C | 100.4°F | Mild fever |
| 39°C | 102.2°F | Moderate fever |
| 40°C | 104°F | High fever / heat wave |
| 100°C | 212°F | Boiling point of water (sea level) |
| 160°C | 320°F | Oven (low) |
| 180°C | 356°F | Oven (baking cakes, cookies) |
| 200°C | 392°F | Oven (roasting) |
| 220°C | 428°F | Oven (high heat, pizza) |
Fahrenheit to Celsius — The Reverse Formula
°C = (°F − 32) × 5/9Example — converting 98.6°F back to Celsius:
- 98.6 − 32 = 66.6
- 66.6 × 5 = 333
- 333 ÷ 9 = 37°C
The converter at the top of this page handles both directions — use the °F → °C tab.
Mental Math Shortcuts (No Calculator Needed)
- Fast °C → °F: Double the Celsius and add 30. Example: 20°C → 40+30 = 70°F. (True answer: 68°F — close enough for everyday use.)
- Fast °F → °C: Subtract 30, then halve it. Example: 70°F → 40÷2 = 20°C. (True answer: 21.1°C.)
- Four anchors to memorise: 0°C = 32°F · 20°C = 68°F · 37°C = 98.6°F · 100°C = 212°F
Why Two Temperature Scales Exist
Celsius was designed by Anders Celsius in 1742 with two logical anchors — 0° at water's freezing point and 100° at boiling. Used by every country except the US, Cayman Islands, and a handful of others.
Fahrenheit was defined by Daniel Fahrenheit in 1724, originally based on brine freezing and body temperature. Still used in the United States for weather, cooking, and body temperature. Its finer granularity (180 degrees between freezing and boiling vs Celsius's 100) makes it slightly more precise for everyday human-scale temperatures.
For conversions involving Kelvin or Rankine as well, use the Unit Converter — it handles all four temperature scales with exact offset formulas.
Frequently Asked Questions
What is the formula to convert Celsius to Fahrenheit?
°F = (°C × 9/5) + 32, also written °F = (°C × 1.8) + 32. Multiply by 9/5 first, then add 32.
What is 37 degrees Celsius in Fahrenheit?
37°C = 98.6°F — normal human body temperature. Calculation: (37 × 1.8) + 32 = 66.6 + 32 = 98.6°F.
What is 100 degrees Celsius in Fahrenheit?
100°C = 212°F — the boiling point of water at sea level. Calculation: (100 × 1.8) + 32 = 180 + 32 = 212°F.
What is 0 degrees Celsius in Fahrenheit?
0°C = 32°F — the freezing point of water. Calculation: (0 × 1.8) + 32 = 0 + 32 = 32°F.
What is 20 degrees Celsius in Fahrenheit?
20°C = 68°F — a comfortable room temperature. Calculation: (20 × 1.8) + 32 = 36 + 32 = 68°F.
What is 30 degrees Celsius in Fahrenheit?
30°C = 86°F — a hot summer day. Calculation: (30 × 1.8) + 32 = 54 + 32 = 86°F.
What is the equation to convert Celsius to Fahrenheit?
°F = (°C × 9/5) + 32. This is also written as °F = (°C × 1.8) + 32. Both give identical results.
What is centigrade to Fahrenheit?
Centigrade is the old name for Celsius — they are the same scale. The formula is °F = (°C × 9/5) + 32.
How do I convert Celsius to Fahrenheit without a calculator?
Quick shortcut: double the °C value and add 30. Example: 25°C → 50+30 = 80°F. (True: 77°F.) Close enough for weather forecasts and cooking estimates.
At what temperature are Celsius and Fahrenheit the same?
-40°. Both scales read exactly -40 at that temperature — the only point where they are equal.
What is C to F calculation?
The C to F calculation is: multiply °C by 1.8, then add 32. So for 25°C: 25 × 1.8 = 45, then 45 + 32 = 77°F.