Temperature Converter

About the Temperature Converter

A temperature converter instantly converts between Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R) — the four temperature scales used in science, engineering, cooking, weather forecasting, and industry. Temperature conversion is one of the most universally needed calculations because the USA uses Fahrenheit for daily weather, weather forecasts, and cooking while virtually every other country uses Celsius, and science uses Kelvin as the absolute temperature scale anchored at the coldest theoretically possible temperature. Our converter handles the full range from absolute zero (0 K = −273.15°C = −459.67°F, the theoretical floor of temperature) through everyday temperatures up to industrial and scientific extremes in the millions of degrees. It includes a reference table of key temperature landmarks — body temperature, water freezing and boiling points, oven temperatures, and weather benchmarks — so conversions always have meaningful context.

How It Works

Exact 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. Rankine to Fahrenheit: °F = °R − 459.67. Key reference points: Absolute zero = 0 K = −273.15°C = −459.67°F. Water freezes at 0°C = 32°F = 273.15 K. Human body temperature = 37°C = 98.6°F = 310.15 K. Water boils at sea level: 100°C = 212°F = 373.15 K. Dry ice (solid CO₂): −78.5°C = −109.3°F. The surface of the Sun: ≈5,500°C = 9,932°F.

Tips & Best Practices

• ✓Quick mental estimate: double the Celsius temperature and add 30 to get approximate Fahrenheit. Example: 20°C → 20×2+30 = 70°F (actual: 68°F). Good enough for everyday temperature sense.
• ✓The magic crossover: −40°C = −40°F — the only temperature where both scales give the same reading. Useful as a calibration reference point.
• ✓Oven temperature guide: 160°C = 320°F (slow); 180°C = 356°F (moderate); 200°C = 392°F (moderately hot); 220°C = 428°F (hot); 240°C = 464°F (very hot).
• ✓Body temperature: 37°C = 98.6°F is normal. Fever begins at 38°C = 100.4°F. High fever: 39.5°C = 103.1°F. Dangerous hyperthermia: above 40°C = 104°F.
• ✓Kelvin has no degree symbol — write "300 K" not "300°K." The Kelvin scale starts at absolute zero and is used in all thermodynamic equations because it is always positive.
• ✓Weather benchmarks: 0°C/32°F = freezing point (ice forms). 10°C/50°F = cool jacket weather. 20°C/68°F = comfortable room temperature. 30°C/86°F = hot summer day. 40°C/104°F = dangerously hot.
• ✓Rankine is Fahrenheit's absolute equivalent: Rankine starts at absolute zero like Kelvin but uses Fahrenheit-sized degrees. Used in some engineering applications, particularly in the USA.
• ✓Temperature and altitude: air temperature drops approximately 6.5°C (11.7°F) per 1,000 metres (3,281 feet) of altitude in the standard atmosphere — relevant for mountain weather forecasting and aircraft cabin temperature.

Who Uses This Calculator

International travellers reading weather forecasts in Celsius when accustomed to Fahrenheit, or vice versa. Home cooks using recipes from different countries with different oven temperature scales. Scientists and students converting between Celsius, Kelvin, and Fahrenheit in physics and chemistry. HVAC engineers working with Rankine and Fahrenheit in thermodynamic calculations. Medical professionals interpreting patient temperatures from different reporting systems. Chefs calibrating sous vide and precision cooking equipment. Weather enthusiasts and meteorology students.