Temperature Converter

Convert temperatures between Celsius, Fahrenheit, and Kelvin scales.

deg F = (deg C x 9/5) + 32; deg C = (deg F - 32) x 5/9; K = deg C + 273.15
20 deg C = 68 deg F = 293.15 K; 100 deg F = 37.8 deg C = 310.9 K; 0 deg C = 32 deg F = 273.15 K

How do I convert Celsius to Fahrenheit?

Formula: degreesF = ( degreesC x 9/5) + 32. Example: 20 degreesC = (20 x 1.8) + 32 = 68 degreesF. Common temps: 0 degreesC = 32 degreesF (freezing), 20 degreesC = 68 degreesF (room temp), 37 degreesC = 98.6 degreesF (body temp), 100 degreesC = 212 degreesF (boiling). Reverse: degreesC = ( degreesF - 32) x 5/9. Example: 75 degreesF = (75-32) x 0.556 = 23.9 degreesC. Most countries use Celsius; US uses Fahrenheit.

What are common temperature reference points?

Key temps in both scales: Absolute zero: -273.15 degreesC = -459.67 degreesF = 0 K. Water freezes: 0 degreesC = 32 degreesF = 273.15 K. Room temp: 20-22 degreesC = 68-72 degreesF. Human body: 37 degreesC = 98.6 degreesF. Water boils: 100 degreesC = 212 degreesF = 373.15 K. Hot day: 30 degreesC = 86 degreesF. Cold day: -10 degreesC = 14 degreesF. Oven baking: 180 degreesC = 350 degreesF. These help visualize temperature scales.

What is Kelvin and when is it used?

Kelvin (K) is absolute temperature scale starting at absolute zero (0 K = -273.15 degreesC), the coldest possible temperature. No negative Kelvin values. Used in: Science, physics, chemistry, engineering, astronomy. Conversion: K = degreesC + 273.15. Example: 20 degreesC = 293.15 K. Note: Say "kelvin" not "degrees kelvin" - correct usage is "300 K" not "300 degreesK". Kelvin has same intervals as Celsius (1 K change = 1 degreesC change), but different zero point.

Why do Celsius and Fahrenheit scales differ?

Different historical development: Celsius (1742): Based on water - 0 degrees = freezing, 100 degrees = boiling (at sea level). Used globally, scientific standard. Fahrenheit (1724): 0 degrees = brine freezing, 96 degrees = body temp (later adjusted to 98.6 degrees). Used primarily in US. Celsius more intuitive (water-based), Fahrenheit more precise for weather (1 degrees F = 0.56 degrees C). Scales meet at -40 degrees (same in both). Most countries switched to Celsius for consistency, except US and few others.