Unit Converters

Free unit converters for length, weight, volume, temperature, area, data storage, time, and speed. Instant, accurate metric and imperial conversions.

A unit converter translates a measurement from one system into another — metric to imperial, watts to horsepower, bytes to gigabytes — without forcing you to memorize or re-derive the conversion factor yourself. Behind every tool on this page is the same idea: multiply or divide by a fixed, internationally recognized constant (defined by standards bodies like the International System of Units, or SI) so the number you get back is exact, not approximate. That matters whether you're a student checking homework, an engineer specifying a part, or someone just trying to figure out how many liters are in a gallon.

Most everyday conversions — length, weight, volume, temperature, speed, time — are linear: the relationship between the two units is a single multiplication factor, so converting 10 miles to kilometers is as simple as multiplying by 1.60934. Others are not. Temperature scales like Celsius and Fahrenheit require an offset as well as a scale factor, and a handful of specialized converters here (frequency-wavelength, for example) are inverse relationships rather than straight-line ones. Each converter on this site is built around the correct formula for its unit pair, not a one-size-fits-all multiplier, so the results stay accurate even for the less intuitive conversions.

Beyond the everyday converters — length, weight, volume, area, temperature, and speed — this page also covers the specialized measurement systems used in engineering, physics, and electronics: torque and moment of inertia for mechanical engineering, electric charge and resistance for circuit design, magnetic flux and field strength for electromagnetism, and radiation exposure and absorbed dose for health physics. Each converter includes a full conversion table alongside the calculator itself, so you can see how a value scales across the whole range of related units rather than getting a single isolated answer.