Conversion Calculator

Temperature is the one conversion on this site that isn't a simple multiply, and understanding why makes the whole thing click. The Celsius and Fahrenheit scales don't share a zero point — 0°C is the freezing point of water, but 0°F is much colder. So converting isn't just rescaling, it's rescaling and shifting. The formula is °F = (°C × 9/5) + 32. The 9/5 stretches the degree size; the +32 slides the zero into place.

Going the other way, you undo both operations in reverse order: °C = (°F − 32) × 5/9. Subtract the 32 offset first, then shrink the degree. The two scales cross at exactly −40°, where −40°C equals −40°F — a handy fact and a good way to remember that the offset and the ratio are both doing real work.

Kelvin is the easy one. It uses the same degree size as Celsius — a one-degree change is identical on both — but its zero is absolute zero, the coldest anything can be, which sits at −273.15°C. So Kelvin is just Celsius plus 273.15: water freezes at 273.15 K and boils at 373.15 K. There are no negative Kelvin values, because there's no temperature below absolute zero. Scientists use Kelvin precisely because it has a true zero, which makes ratios meaningful in a way Celsius and Fahrenheit can't manage.

The practical reference points are worth memorizing. Water freezes at 0°C / 32°F and boils at 100°C / 212°F. Body temperature is 37°C / 98.6°F. A comfortable room is around 20–22°C / 68–72°F. A moderate oven is 180°C / 356°F. Because the conversion isn't a clean multiple, eyeballing these anchors and interpolating beats trying to do (°C × 9/5) + 32 in your head every time.