Unit converter
Fourteen kinds of units, exact factors, and answers as you type.
How it works
- 01Pick what you are converting: length, weight, temperature, volume or one of ten more.
- 02Type a number on either side and choose the units. The search box finds any unit, even in another category.
- 03Read the answer, copy it, or scan the table showing your value in every unit at once.
Questions
›How accurate are the conversions?
Factors use the exact definitions wherever they exist: an inch is exactly 2.54 cm, a pound exactly 0.45359237 kg and a US gallon exactly 231 cubic inches. Answers are rounded to the significant digits you choose (up to 15), and a "≈" sign tells you when what you see is rounded.
›What is the difference between MB and MiB?
A megabyte (MB) is 1,000,000 bytes, while a mebibyte (MiB) is 1,048,576 bytes (2²⁰). Drive makers use the decimal units, but Windows counts in binary units and labels them "GB", which is why a 1 TB drive shows up as about 931 GB.
›Why do US and UK cups, pints and gallons differ?
The two systems defined them separately. A US gallon is 3.785 liters and an imperial (UK) gallon 4.546 liters, and a US pint holds 16 fluid ounces while a UK pint holds 20 (slightly smaller) ones. Many recipes outside the US use a metric cup of 250 mL, so all three cups are in the list.
›Why does L/100 km go down when mpg goes up?
Miles per gallon measures distance per unit of fuel, while liters per 100 km measures fuel per unit of distance, so one is the inverse of the other. To get L/100 km, divide 235.215 by US mpg, or 282.481 by UK mpg.
›Is my data uploaded anywhere?
No. This tool runs entirely in your browser, and Rounder never sends what you type or drop in to a server, ours or anyone else's. Once the page has loaded, along with any AI model the tool uses, it even works offline.
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