How to Convert Celsius to Fahrenheit - Formula, Chart and Easy Tricks
Learn the exact formula to convert Celsius to Fahrenheit, get a quick reference chart for common temperatures, and discover a simple mental math shortcut anyone can use.
Why You Need to Convert Celsius to Fahrenheit
Temperature is one of the most frequently converted measurements in everyday life. If you live in Europe and watch an American weather forecast, or follow a recipe from a US cookbook, or simply want to know what 100°F actually feels like — you need to convert between Celsius and Fahrenheit. This guide gives you everything you need: the exact formula, a quick reference chart, a mental math shortcut, and real-world examples.
The Celsius to Fahrenheit Formula
The mathematically exact formula is:
°F = (°C × 9/5) + 32
Which is the same as:
°F = (°C × 1.8) + 32
To use it, multiply the Celsius value by 1.8 and then add 32. That's it.
Step-by-Step Examples
Convert 0°C to Fahrenheit
(0 × 1.8) + 32 = 0 + 32 = 32°F
This is the freezing point of water — one of the easiest reference points to memorise.
Convert 20°C to Fahrenheit
(20 × 1.8) + 32 = 36 + 32 = 68°F
A comfortable room temperature.
Convert 37°C to Fahrenheit
(37 × 1.8) + 32 = 66.6 + 32 = 98.6°F
Normal human body temperature — another essential reference point.
Convert 100°C to Fahrenheit
(100 × 1.8) + 32 = 180 + 32 = 212°F
The boiling point of water at standard atmospheric pressure.
Fahrenheit to Celsius Formula
To go in the opposite direction, use:
°C = (°F − 32) × 5/9
Which is the same as:
°C = (°F − 32) ÷ 1.8
Example: Convert 98.6°F to Celsius
(98.6 − 32) ÷ 1.8 = 66.6 ÷ 1.8 = 37°C
Quick Reference Temperature Chart
| Celsius (°C) | Fahrenheit (°F) | What It Feels Like |
|---|---|---|
| -40°C | -40°F | Extreme cold — both scales meet here |
| -20°C | -4°F | Very cold winter, frostbite risk |
| -10°C | 14°F | Freezing cold, heavy coat needed |
| 0°C | 32°F | Freezing point of water |
| 5°C | 41°F | Cold, winter jacket weather |
| 10°C | 50°F | Cool autumn or spring day |
| 15°C | 59°F | Mild, light jacket weather |
| 20°C | 68°F | Comfortable room temperature |
| 25°C | 77°F | Warm and pleasant |
| 30°C | 86°F | Hot summer day |
| 37°C | 98.6°F | Normal body temperature |
| 40°C | 104°F | Dangerously hot, heat stroke risk |
| 100°C | 212°F | Boiling point of water |
The Easy Mental Math Shortcut
If you just need a rough estimate without a calculator, use this trick:
Double the Celsius temperature, then add 30.
Example: 20°C → (20 × 2) + 30 = 70°F. The exact answer is 68°F, so this gives you a close estimate.
This shortcut works best for temperatures between -10°C and 30°C, which covers most everyday weather situations. Outside that range, use the exact formula.
Cooking Temperature Reference
Oven temperatures are a common source of confusion between Celsius and Fahrenheit. Here are the most useful cooking temperatures converted:
| Description | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| Very low oven | 120°C | 250°F |
| Low oven | 150°C | 300°F |
| Moderate oven | 180°C | 350°F |
| Hot oven | 200°C | 400°F |
| Very hot oven | 220°C | 425°F |
| Broiling/Grilling | 230°C | 450°F |
Key Temperature Facts
- Water freezes at 0°C / 32°F
- Water boils at 100°C / 212°F at sea level
- Normal body temperature is 37°C / 98.6°F
- The two scales cross at exactly -40° — the only temperature that is the same in both systems
- Absolute zero (the coldest possible temperature) is -273.15°C / -459.67°F
Convert Any Temperature Instantly
Use our free temperature converter to instantly convert between Celsius, Fahrenheit, and Kelvin. Just enter a number and get the result in real time — no formula needed.