Celsius to Fahrenheit Quick Reference — Common Temperatures Converted

Temperature conversion comes up all the time. You're reading a US recipe that says preheat the oven to 375°F. You're checking a weather forecast for a trip to London and it says 18°C. You hear a body temperature of 101.3°F and wonder if that's serious. Having a few reference points memorized saves you from doing the math every time.

The exact formulas

To convert Celsius to Fahrenheit: multiply by 9, divide by 5, then add 32. Shorter version: multiply by 1.8 and add 32.

To convert Fahrenheit to Celsius: subtract 32, multiply by 5, divide by 9. Shorter version: subtract 32 and divide by 1.8.

The one temperature where both scales agree is -40. That's the same in both systems, which makes it a useful anchor point.

A mental shortcut that's close enough

For everyday estimates, double the Celsius temperature and add 30. 20°C becomes (40 + 30) = 70°F. The actual answer is 68°F. Close enough for checking whether to pack a jacket.

For the reverse, subtract 30 from the Fahrenheit temperature and halve it. 70°F becomes (40 / 2) = 20°C. Again, close enough for practical purposes.

Reference points to memorize

• 0°C / 32°F — water freezes, roads get icy
• 10°C / 50°F — cool autumn day, jacket needed
• 20°C / 68°F — comfortable, mild spring
• 30°C / 86°F — warm summer day
• 37°C / 98.6°F — normal body temperature
• 40°C / 104°F — fever threshold, dangerous heat
• 100°C / 212°F — water boils at sea level
• 180°C / 356°F — common baking temperature
• 220°C / 428°F — high-heat roasting

Cooking temperatures specifically

US recipes almost always use Fahrenheit. UK and Indian recipes usually use Celsius or gas marks. A few temperatures worth knowing by heart: 175°C = 350°F (moderate baking), 200°C = 400°F (hot roasting), 230°C = 450°F (very high heat for pizzas).

For anything more specific, use the Unit Converter to get precise values instantly.