The Formulas
°C = (°F − 32) × 5/9
Fahrenheit to Celsius: subtract 32, multiply by 5, divide by 9
°F = (°C × 9/5) + 32
Celsius to Fahrenheit: multiply by 9, divide by 5, add 32
Worked Examples
Convert 350°F to Celsius:
°C = (350 − 32) × 5/9 = 318 × 5/9 = 176.7°C (commonly rounded to 175°C or 180°C)
Convert 200°C to Fahrenheit:
°F = (200 × 9/5) + 32 = 360 + 32 = 392°F (commonly rounded to 400°F)
Complete Oven Temperature Chart
| Description | °F | °C | Gas Mark |
|---|---|---|---|
| Very Cool | 225 | 107 | ¼ |
| Cool | 250 | 121 | ½ |
| Very Low | 275 | 135 | 1 |
| Low | 300 | 149 | 2 |
| Moderately Low | 325 | 163 | 3 |
| Moderate | 350 | 177 | 4 |
| Moderately Hot | 375 | 191 | 5 |
| Hot | 400 | 204 | 6 |
| Very Hot | 425 | 218 | 7 |
| Very Hot | 450 | 232 | 8 |
| Extremely Hot | 475 | 246 | 9 |
| Broil | 500 | 260 | 10 |
Why Two Temperature Scales?
Fahrenheit (1724) was defined by Daniel Gabriel Fahrenheit using three reference points: 0°F = brine freezing point, 32°F = water freezing point, 96°F ≈ body temperature. Used primarily in the United States.
Celsius (1742) was defined by Anders Celsius with simpler reference points: 0°C = water freezing point, 100°C = water boiling point. Used by most countries worldwide.
Gas Mark is a temperature scale used on gas ovens in the UK, Ireland, and some Commonwealth countries. Gas Mark 1 = 275°F = 135°C, with each mark representing a 25°F increase.
Quick Mental Math Tricks
- Rough °F to °C: Subtract 30, divide by 2. (350°F → 320/2 = 160°C, actual = 177°C — off by ~10%, but fast)
- Exact crossover: −40° is the same in both scales (−40°F = −40°C)
- Common anchors: 32°F = 0°C (freezing), 212°F = 100°C (boiling), 72°F ≈ 22°C (room temp)