Units

Metric, imperial, scientific — instant conversion, 100% local.

Equivalences

Conversion performed entirely in your browser — no data is sent to a server.

How a unit conversion works

Converting means multiplying a value by a fixed ratio between two ways of measuring the same quantity. Going from metres to feet means multiplying by 3.280840; going back to metres, dividing by that same number. The station applies this principle to fifteen families of quantities — length, mass, volume, area, temperature, speed, time, digital data, energy, pressure, and five electrical quantities (voltage, current, resistance, frequency, charge) — and shows every equivalence in a category at once, without you having to pick the target unit.

The odd one out: temperature

Celsius, Fahrenheit and Kelvin don't convert by a simple factor, because their scales share neither the same origin nor the same step. You have to shift the zero and then change the size of the degree.

°F = °C × 9/5 + 32  ·  K = °C + 273.15

That's why a 1 °C difference equals exactly 1 K but 1.8 °F, while a temperature of 0 °C corresponds to 273.15 K and 32 °F.

A few reference points

UnitEquivalent
1 inch (in)2.54 cm (exact)
1 foot (ft)30.48 cm
1 mile (mi)1.609 km
1 pound (lb)453.6 g
1 US gallon3.785 L
1 bar100,000 Pa ≈ 0.987 atm
1 horsepower (hp)735.5 W
1 knot1.852 km/h
Remember: for digital data, a commercial "GB" is 1000 MB, but an operating system often counts in 1024 (then called GiB). A drive sold as "1 TB" therefore shows about 931 GiB once formatted: not a loss, just two different conventions.

Frequently asked questions

Are the conversions exact?

The factors used are the reference values (BIPM, NIST). The display is rounded for readability, but the calculation keeps the full precision of a floating-point number internally.

Do my values leave my device?

No. Once the page has loaded, the converter works offline: no value you enter passes through a server.

Why do energy or electricity have so many units?

These categories gather units from different fields (electronics, thermal, mechanical). Choosing the category filters the list down to units that are actually comparable.