Unit Converter
Convert length, mass, volume, area, speed, data, time and temperature units instantly.
Runs in your browser — files never leave your device
How it works
Pick one of eight categories — length, mass, volume, area, speed, data, time, or temperature — choose a From unit and a To unit, and type a value. The result appears instantly and recalculates on every keystroke; there is no convert button and no page reload. Switching category resets the unit pickers to sensible defaults so you can jump from miles to megabytes in two clicks.
Under the hood, every unit carries an exact factor to a base unit — the meter for length, the kilogram for mass, the liter for volume — and a conversion is simply value × from-factor ÷ to-factor. The factors are the standard definitions: the international mile is exactly 1,609.344 m, the avoirdupois pound exactly 0.45359237 kg, the US gallon exactly 3.785411784 liters. Temperature is the one category that cannot work that way, because °C, °F, and K have different zero points, so it uses the exact formulas instead: 37 °C converts to 98.6 °F, and 100 °F to 37.778 °C.
Some worked examples, exactly as the tool displays them: 6 ft = 182.88 cm, 5 mi = 8.047 km, 150 lb = 68.039 kg, 2 weeks = 336 hours, 100 km/h = 62.137 mph, and 1 hectare = 2.471 acres. Results are rounded to at most three decimal places for display; the arithmetic itself runs at full floating-point precision.
Two conventions are worth knowing before you rely on the numbers. The data category is binary: 1 KB = 1,024 bytes and 1 GB = 1,024 MB, matching how operating systems report file sizes rather than how drive makers advertise capacity. And the volume units are US customary — the gallon here is 3.785 liters and the cup 236.588 ml, so imperial (UK) gallons and metric cups will differ. Likewise, t means the metric tonne of exactly 1,000 kg, not the US short ton.
Frequently asked questions
- Which categories and units are supported?
- Eight categories. Length: m, km, cm, mm, mi, yd, ft, in. Mass: kg, g, mg, lb, oz, t. Volume: l, ml, m³, gal, qt, cup. Area: m², km², ha, ft², ac. Speed: m/s, km/h, mph, knots. Data: B, KB, MB, GB, TB. Time: s, min, h, day, week. Temperature: °C, °F, K.
- Are the volume units US or imperial?
- US customary. The gallon is 3.785 liters, the quart is 0.946 liters, and the cup is 236.588 ml. The UK imperial gallon (about 4.546 liters) is a different unit and is not included, so British recipe or fuel figures will not match.
- Why does 1 GB show 1,024 MB and not 1,000?
- The data category uses binary (1024-based) factors: 1 KB = 1,024 bytes, 1 MB = 1,024 KB, and so on. That matches how operating systems traditionally report file sizes. Drive manufacturers advertise decimal units (1 GB = 1,000,000,000 bytes), which is why a “1 TB” drive shows up smaller in your file manager.
- Is “t” a US ton or a metric tonne?
- A metric tonne: exactly 1,000 kg, which the tool displays as 2,204.623 lb. The US short ton (2,000 lb) and UK long ton are different units and are not included.
- How accurate are the conversions?
- The factors are the exact standard definitions where one exists — the international mile is 1,609.344 m, the pound is 0.45359237 kg, the US gallon is 3.785411784 liters — and temperature uses the exact °C/°F/K formulas. Results are rounded to at most three decimal places for display, so 10 km shows as 6.214 mi even though the full value is 6.21371… .
- Why is temperature handled differently from the other categories?
- Every other category converts by multiplying with a ratio, but temperature scales have shifted zero points, so a ratio is not enough. The tool applies the standard formulas instead: °F = °C × 9/5 + 32 and K = °C + 273.15. That is why 0 °C is 32 °F, not 0 °F.
- Does the converter send my numbers anywhere?
- No. The factors ship with the page and the arithmetic runs in your browser, so conversions are instant and work offline once the page has loaded.