Universal converter
Unit Converter
Eight categories, over seventy units, one converter. Length, weight, temperature, area, volume, speed, digital storage and time, with every unit in the category converted at once so you can read any combination in a single glance.
Four steps
How to convert units
- 1
Pick a category
Choose length, weight, temperature, area, volume, speed, data or time.
- 2
Enter a value
Type the number you want to convert, the result updates as you type.
- 3
Choose the units
Set the source and target units, or press swap to reverse the direction.
- 4
Copy the result
Use the copy button, or read the full breakdown across every unit below.
Eight categories in one tool
Most conversion sites make you pick a category before you see anything. This one shows every unit in the active category simultaneously, which matters when you are working across systems, a designer moving between millimetres, inches, picas and pixels, or a cook translating a European recipe into US cups.
| Category | Units | Common conversions |
|---|---|---|
| Length | 14 | nm, µm, mm, cm… |
| Weight | 8 | mg, g, kg, t… |
| Temperature | 3 | °C, °F, K… |
| Area | 9 | mm², cm², m², ha… |
| Volume | 11 | ml, L, m³, tsp… |
| Speed | 5 | m/s, km/h, mph, kn… |
| Digital storage | 8 | B, KB, MB, GB… |
| Time | 8 | ms, s, min, h… |
Exact factors, not approximations
The relationships between imperial and metric units are defined exactly by international agreement: one inch is exactly 25.4 mm, one pound is exactly 453.59237 g, and one mile is exactly 1,609.344 m. Those exact values are what this converter uses. Results are rounded for readability, but the arithmetic behind them carries full double precision.
The three traps worth knowing
- Temperature is affine. The scales are offset as well as scaled, so conversion needs a formula, not a factor.
- Area factors are squared. A foot is 0.3048 m, but a square foot is 0.0929 m², square the length factor, do not reuse it.
- US and imperial volumes differ. Same names, different sizes. A US gallon is 3.785 L; an imperial gallon is 4.546 L.
Converting for print and screen
If you are converting in order to set up a sheet of paper, the graph paper generator takes spacing directly in millimetres, and there are ready-made presets for quarter-inch and 5 mm grids if you would rather not do the arithmetic. To verify a printed result, the calibrated on-screen ruler measures in both systems.
Answers
Frequently asked questions
°F = (°C × 9/5) + 32. The converter handles this automatically.