Unit Converter — Length, Weight, Temperature and More
Write the unit next to the number and get every other unit back.
Runs on your device What you paste is processed by your own browser. It is never sent to a server, and it is not stored anywhere after you leave the page.
Short answer
Units can be converted for free in a web browser by writing the value and its unit on one line — 5 km, 12 lb, 100 °F — and reading the result in every other unit of the same family. Eight families are covered: length, weight and mass, temperature, area, volume, speed, data size and time. The unit is read from the line itself, so a column of mixed values converts in one pass, and temperature is handled with its offset rather than as a bare scale factor, so 0 °C comes back as 32 °F.
At a glance
| Accepts | One value and unit per line — 5 km, 12 lb, 100 °F |
|---|---|
| Produces | A table of every unit in that family |
| Processing | In your browser |
| Price | Free, no limits |
| Account | Not required |
Most unit converters ask for three things: a number, a unit to convert from, and a unit to convert to. Two of those are a wasted click. The unit is already written next to the number in whatever you copied it out of, and the unit you want is whichever row you look at — so this page reads the first and shows all of the second.
That is also what makes a pasted column work. A packing list with kilograms and pounds in it, or a spec sheet quoting both inches and millimetres, converts in one pass instead of one row at a time. Naming a family in the dropdown asks for the opposite behaviour: with Time selected, 12 m is refused rather than quietly read as twelve metres.
How to use it
- 1
Type a value and its unit
One per line, with the unit after the number: 5 km, 12 lb, 100 °F, 2.5 GB.
- 2
Leave the family on automatic
The unit written on the line decides it. Name a family only to rule out a symbol that means something else elsewhere.
- 3
Convert
Each line comes back as a table of that value in every unit of its family.
- 4
Copy the result
Copy to the clipboard, or download it as a text file.
Frequently asked questions
Which units does it know?
Length: mm, cm, m, km, in, ft, yd, mi and nautical miles. Weight: mg, g, kg, tonnes, oz, lb and stone. Temperature: °C, °F and K. Area: mm² to km², hectares, in², ft², yd², acres and mi². Volume: ml, l, m³, in³, ft³, the US fluid ounce, cup, pint, quart and gallon, and the imperial gallon. Speed: m/s, km/h, mph, knots and ft/s. Data: B to TB and KiB to TiB. Time: ms, s, min, h, days and weeks.
Are the gallons US or imperial?
US, along with the pint, quart, cup and fluid ounce — that is what gal means on most of the web. The imperial gallon has a row of its own, because it is a fifth larger and a fuel figure read in the wrong one is wrong by a fifth.
Why are both KB and KiB shown?
Because both are in use and neither is wrong. A drive sold as 1 TB holds 10^12 bytes, which an operating system counting in powers of two reports as 0.909 TiB. Seeing both rows is what explains the space that appears to be missing.
Can the unit be written as a word?
Yes. Kilometres, pounds, fahrenheit and the rest of the common names are accepted alongside the symbols, as are the Chinese names — 公里, 公斤, 摄氏度 — and the answer is the same table either way.
How precise are the conversions?
The factors are the exact defined ones: an inch is 25.4 mm, a pound is 0.45359237 kg, a nautical mile is 1852 m. Results print to twelve significant digits unless you pick a fixed number of decimals, which is more precision than a hand-typed input carries.