Celsius to Fahrenheit: Temperature Conversion Made Simple
Whether you are reading a weather forecast, following a recipe, or adjusting a thermostat abroad, temperature conversion is a daily need for millions of people. Here is everything you need to know.
The world uses two major temperature scales for everyday life: Celsius (°C), used by almost every country, and Fahrenheit (°F), used primarily in the United States. A third scale, Kelvin (K), is used in science and engineering. Each scale was developed independently and is defined differently, which is why converting between them requires more than a simple multiplier.
The Conversion Formulas
- Celsius to Fahrenheit: °F = (°C × 9/5) + 32
- Fahrenheit to Celsius: °C = (°F − 32) × 5/9
- Celsius to Kelvin: K = °C + 273.15
- Kelvin to Celsius: °C = K − 273.15
- Fahrenheit to Kelvin: K = (°F − 32) × 5/9 + 273.15
Essential Reference Points
Memorising a handful of key reference temperatures makes conversion much more intuitive:
- Absolute zero: −273.15°C / −459.67°F / 0 K
- Water freezes: 0°C / 32°F / 273.15 K
- Room temperature: ~20°C / 68°F / 293 K
- Body temperature: 37°C / 98.6°F / 310 K
- Hot summer day: 35°C / 95°F / 308 K
- Fever threshold: 38°C / 100.4°F
- Water boils (sea level): 100°C / 212°F / 373 K
- Oven for baking: 180°C / 356°F
Quick Mental Approximations
The exact formula (multiply by 9/5 and add 32) is precise but awkward for mental arithmetic. Two useful shortcuts:
- Rough °C to °F: double the Celsius temperature and add 30 — e.g. 20°C: 20 × 2 = 40, + 30 = 70°F (exact: 68°F)
- Rough °F to °C: subtract 30 and halve — e.g. 80°F: 80 − 30 = 50, ÷ 2 = 25°C (exact: 26.7°C)
These approximations are off by a couple of degrees but work well for weather and everyday temperature ranges.
Why Two Scales Exist
The Fahrenheit scale was proposed by Daniel Gabriel Fahrenheit in 1724. He set 0°F as the temperature of a brine solution and 96°F as human body temperature — a scale that felt intuitive to him. The Celsius scale, proposed by Anders Celsius in 1742, tied its zero and 100 points to the freezing and boiling of water — a more scientifically logical anchor. The Kelvin scale, developed in the 1800s by Lord Kelvin, sets zero at absolute zero, the lowest theoretically possible temperature, making it ideal for scientific calculations where negative temperatures are problematic.
Temperature in Cooking
Recipe temperatures cause frequent confusion when cooking across international recipes. Common oven temperatures:
- Low (slow cook): 120–150°C / 250–300°F
- Moderate: 160–180°C / 325–350°F
- Moderately high: 190–200°C / 375–400°F
- High: 220°C / 425°F
- Very high (pizza): 250°C+ / 480°F+
Convert Any Temperature Instantly
Our free Temperature Converter handles Celsius, Fahrenheit, and Kelvin conversions instantly. Just enter a value, select your starting unit, and see all three scales at once — no sign-up, no ads interrupting your result.