Temperature Converter

Why There Are So Many Temperature Scales

It seems unnecessarily complicated — water boils at 100°C, 212°F, and 373.15 K, all at the same time. Three numbers for the same physical fact. The reason is historical: temperature scales were each invented independently by scientists working in different countries and contexts, and different ones caught on in different places before any international standardization happened.

This converter handles all seven historically significant temperature scales in one place. Whether you're checking weather forecasts from a different country, working on a science problem, or just satisfying genuine curiosity, type in any temperature and all seven equivalents appear simultaneously.

The Conversion Formulas

Every scale converts through Celsius as the common intermediate:

The only notable cross-conversion to memorize: −40 is the one temperature where Fahrenheit and Celsius are equal (−40°C = −40°F). This is also the point where the scales geometrically intersect if you draw them on a graph.

The Seven Scales Explained

Celsius (°C) was developed by Anders Celsius in 1742 and is used by nearly every country in the world for everyday temperature. The scale places water's freezing point at 0° and boiling point at 100° at sea-level atmospheric pressure — an intuitive, practical division.

Fahrenheit (°F) was developed by Daniel Gabriel Fahrenheit in 1724 and remains the official scale of the United States, Belize, and a few territories. Its reference points (32° for freezing, 212° for boiling) seem arbitrary because Fahrenheit originally calibrated against a brine solution. For human weather experience, the 0–100°F range maps loosely to "extreme cold" to "extreme heat," which some argue makes it intuitively useful for weather.

Kelvin (K) is the SI unit of thermodynamic temperature used in all scientific contexts. It starts at absolute zero — the theoretical minimum temperature where molecular motion ceases entirely (−273.15°C). Kelvin uses the same step size as Celsius, just offset. Physicists use Kelvin because it gives thermodynamically meaningful ratios: 200K is genu...