Convert Celsius to Fahrenheit instantly. Used in cooking, weather, medicine and travel.
| Unit | Name | Value |
|---|---|---|
| °F | Fahrenheit | 33.8 |
| K | Kelvin | 274.15 |
| °R | Rankine | 493.47 |
Multiply by 9/5 then add 32. Formula: °F = °C × 9/5 + 32. Example: 20°C × 9/5 + 32 = 68°F. Reverse: °C = (°F − 32) × 5/9.
| Celsius (°C) | Fahrenheit (°F) | Real-world context |
|---|---|---|
| -40°C | -40°F | Unique crossover — both scales are equal here |
| -18°C | 0°F | Typical home freezer temperature |
| 0°C | 32°F | Freezing point of water |
| 10°C | 50°F | Cool spring morning in northern Europe |
| 20°C | 68°F | Comfortable room temperature |
| 25°C | 77°F | Warm summer day |
| 37°C | 98.6°F | Normal human body temperature |
| 40°C | 104°F | Fever threshold requiring medical attention |
| 100°C | 212°F | Boiling point of water at sea level |
| 180°C | 356°F | Standard cake baking temperature |
| 220°C | 428°F | Pizza oven temperature |
For rough mental maths: double the °C value and add 30. Example: 25°C → 50+30 = 80°F (actual: 77°F). Error is only ±3°F — fine for everyday use.
Lock in: 0°C=32°F, 10°C=50°F, 20°C=68°F, 37°C=98.6°F, 100°C=212°F. Interpolate between them for any other value.
Normal body temp is 37°C = 98.6°F. Fever starts at 38°C (100.4°F). Worth memorising for travel to the US — American thermometers always show °F.
For oven temps: halve the Fahrenheit value and subtract 10 to estimate Celsius. 350°F ÷ 2 − 10 = 165°C (actual: 177°C). Close enough for most recipes.
Real professions and situations that need °C to °F conversion
The Celsius scale (symbol: °C) is the world standard for everyday and scientific temperature measurement. Proposed by Swedish astronomer Anders Celsius in 1742, he originally defined 0° as the boiling point of water and 100° as the freezing point — the inverse of today's system. Carl Linnaeus inverted the scale to its modern intuitive form shortly after.
Renamed from "centigrade" to "Celsius" in 1948 at the 9th General Conference on Weights and Measures, the scale is now defined relative to the Kelvin: 0°C = 273.15 K exactly. A fascinating historical note: Celsius was primarily an astronomer who developed the scale to standardise calibration points for atmospheric refraction correction tables — he never imagined it becoming the global temperature standard.
The Fahrenheit scale (symbol: °F) was developed by German physicist Daniel Gabriel Fahrenheit in 1724. He set 0°F as the temperature of a brine ice mixture, and 96°F as human body temperature (later corrected to 98.6°F). Water freezes at 32°F and boils at 212°F — a span of exactly 180 degrees.
Fahrenheit dominated scientific use in English-speaking countries for over two centuries. The US is now the only major country still using it for everyday temperature. An interesting quirk of Fahrenheit's design: the 180-degree span between freezing (32°F) and boiling (212°F) was likely intentional — 180 is exactly 3×60, fitting neatly with the base-60 mathematics familiar to scientists of his era.
Common use: Celsius-to-Fahrenheit conversion is one of the most searched unit conversions globally, driven by US-international travel, recipe sharing between American and European food cultures, and medical communication across health systems. The formula °F = °C × 9/5 + 32 is worth memorising for anyone who regularly works across these two measurement worlds.