Convert any measurement in seconds with this free unit converter
Switching between metric and imperial measurements shouldn't mean digging out an old physics textbook or scribbling factors on the back of an envelope. This unit converter brings the eight categories you reach for most — length, weight and mass, temperature, area, volume, speed, time and digital data storage — into a single screen. You type a number, pick what you have and what you want, and the answer appears the instant you stop typing. There is nothing to install, no account to create, and no waiting for a page to reload.
It is built for anyone who runs into mixed units during the day: a home cook halving an American recipe that lists cups and ounces, a student checking homework in metres and feet, a traveller working out kilometres per hour from a mile-marked speed limit, a tradesperson squaring up an area in both square metres and square feet, or a developer translating gigabytes into bytes. Because every category sits behind a single tap, you never have to hunt for a separate page — the same box handles all of them, and the layout stays comfortable on a phone as well as a desktop.
How to use it
- Tap a category from the scrollable row at the top — Length, Weight, Temperature, Area, Volume, Speed, Time or Data.
- Type the value you want to convert into the From box and choose its unit from the dropdown.
- Choose the To unit; the converted result fills in immediately, with no convert button to press.
- Read the highlighted summary line under the boxes — it shows the full conversion plus the rate for one unit, so you can sanity-check the maths.
- Glance at the chips below to see your value expressed in every other unit in that category at once, and use the round swap button to flip the two units and reverse the direction.
How the conversions are calculated
Most categories work the same simple way: each unit is stored with a factor that says how many base units it equals — for length the base is the metre, so a foot is 0.3048 and a mile is 1609.344. To convert, the tool multiplies your value into base units and divides into the target unit, which keeps every result consistent to a fraction of a millimetre. Temperature is the one exception, because Celsius, Fahrenheit and Kelvin do not share a zero point. There a proper formula is used — for example Fahrenheit becomes Celsius via (°F − 32) × 5⁄9, and Kelvin is Celsius plus 273.15 — so freezing, boiling and body-temperature values all come out exactly right rather than being scaled like a plain ratio.
Metric, imperial and the units you'll find here
Each category mixes SI (metric) and customary units so you can cross between systems without a second tool. Length runs from millimetres up to the nautical mile; weight covers tonnes down to milligrams alongside pounds, ounces and stone. Volume deliberately uses US measures — gallon, quart, pint, cup, fluid ounce, tablespoon and teaspoon — which is what most online recipes assume, and it sits beside litres and millilitres for metric cooks. Data storage uses the binary convention where a kilobyte is 1024 bytes and a megabyte is 1024 kilobytes, matching how operating systems usually report file and drive sizes, while bits are included for bandwidth maths. Speed spans km/h, mph, m/s, ft/s and knots for anything from a jog to a flight plan.
Accuracy, rounding and common mistakes
Results lean on standard international conversion factors, so they are dependable for schoolwork, kitchens, workshops and professional estimates alike. Numbers are rounded for readability — very large or very small results switch to compact scientific notation rather than printing a screen full of digits — but the underlying calculation stays precise. The pitfalls to watch for are usually about which unit you picked: a US gallon is smaller than an imperial gallon, a stone is fourteen pounds, and a tonne is a thousand kilograms, not a US "short ton". When a recipe or spec doesn't say, assume US volume units here. For mission-critical engineering or legal work, always confirm against the relevant published standard before you rely on a figure.
Private by design — everything runs in your browser
Every calculation happens locally on your device. Nothing you type is sent to a server, stored, or shared, and you can keep converting even with a flaky connection once the page has loaded. That makes it quick, safe to use with sensitive numbers, and friendly to your data allowance — no uploads, no tracking of what you convert, just an answer the moment you need one.