Convert between Celsius, Fahrenheit, and Kelvin instantly. Includes cooking temperatures, weather references, body temperature, and the exact formulas to do conversions yourself.
Memorizable anchor temperatures to estimate conversions quickly
Enter any temperature in Celsius, Fahrenheit, or Kelvin and get instant precise conversions to all three scales.
Open Unit Converter →There are three temperature scales in common use. Here are all 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
The factor 9/5 (= 1.8) accounts for the difference in degree size between the scales. Fahrenheit degrees are smaller — 100°C spans 180°F (from 32 to 212), so each Celsius degree = 1.8 Fahrenheit degrees.
Celsius (formerly Centigrade) was proposed in 1742 by Swedish astronomer Anders Celsius and defined by the freezing (0°) and boiling (100°) points of water at sea level. This clean 0-100 range for water's liquid state made it ideal for scientific use, and it's now the standard in 95% of countries.
Fahrenheit was proposed by German physicist Daniel Gabriel Fahrenheit in 1724 and was calibrated differently: 0°F was the coldest stable temperature he could create (a brine of ice and salt), and 96°F was body temperature (later adjusted to 98.6°F). The US, Belize, Cayman Islands, and Bahamas still use Fahrenheit for everyday weather and cooking.
Kelvin, introduced by Lord Kelvin in 1848, is the SI base unit for temperature. It starts at absolute zero (−273.15°C = −459.67°F) — the theoretical minimum temperature where molecular motion stops. Kelvin is used in physics, chemistry, and astrophysics but not in everyday contexts.
Instead of always calculating, memorizing key anchor temperatures helps build intuition:
Cold: −40°C/F (same!), 0°C/32°F (freezing), 10°C/50°F (chilly), 15°C/59°F (cool)
Comfortable: 20°C/68°F (room temp), 22°C/72°F (ideal indoor), 25°C/77°F (warm)
Hot: 30°C/86°F (hot day), 37°C/98.6°F (body temp), 40°C/104°F (dangerous heat)
Cooking: 100°C/212°F (boiling), 175°C/350°F (baking standard), 230°C/450°F (high roast)
Following recipes that use a different temperature scale is one of the most common conversion needs. Complete oven temperature reference:
150°C = 300°F (very low, slow cooking) | 160°C = 325°F (low-moderate) | 175°C = 347°F (standard baking) | 180°C = 356°F (moderate high) | 190°C = 374°F | 200°C = 392°F | 220°C = 428°F (high) | 240°C = 464°F (very high/broil)
For quick conversion: Multiply Celsius by 2, subtract 10% of that result, then add 32. Example: 180°C → 360 − 36 + 32 = 356°F. This approximation is accurate to within 1–2°F for typical cooking temperatures.
Normal body temperature is 37°C = 98.6°F, though individual variation is normal (36.1–37.2°C / 97–99°F). Fever thresholds: Low-grade fever: 37.3–38°C (99.1–100.4°F). Moderate fever: 38–39°C (100.4–102.2°F). High fever: 39–40°C (102.2–104°F). Dangerous: above 40°C (104°F) — requires medical attention. The 98.6°F figure is the most common reference, though it's an average and human temperature varies throughout the day.
Kelvin is unique because it has no negative values — it starts at absolute zero (0 K = −273.15°C), the point at which all molecular thermal motion would theoretically cease. This makes Kelvin essential for equations in thermodynamics, gas laws, and astronomy. Stars are measured in Kelvin: our Sun's surface is ~5,778 K (5,505°C / 9,941°F). The cosmic microwave background radiation — the afterglow of the Big Bang — is 2.73 K, just barely above absolute zero.
°F = (°C × 9/5) + 32. Example: 25°C = (25×1.8)+32 = 45+32 = 77°F. Mental shortcut: double the Celsius, subtract 10%, add 32.
°C = (°F − 32) × 5/9. Example: 98.6°F = (98.6−32)×0.5556 = 66.6×0.5556 = 37°C. Mental shortcut: subtract 32, then halve it and add 10%.
−40°. Both scales equal −40 at this point: −40°C = −40°F. This is the only crossover point, found by solving C = F in the conversion formula.
150°C=300°F | 175°C=347°F (standard baking) | 180°C=356°F | 200°C=392°F | 220°C=428°F | 230°C=450°F. The classic "350°F" bake = 177°C.