Unit Converter
Convert length, weight, temperature, volume and more, in both directions.
The conversion is arithmetic done in this page. Nothing you type is sent anywhere.
Unit conversion is the sort of arithmetic nobody wants to be doing at the moment they need it: halfway through a recipe, standing in a hardware shop, reading a spec sheet written for a different continent.
More about Unit Converter
This converter covers ten families — length, weight, temperature, volume, area, speed, digital storage, time, energy and pressure — and shows the answer in every unit of the family at once, not just the one you asked for. That last part matters more than it sounds. Somebody converting a recipe usually wants millilitres and cups; somebody checking a drive wants gigabytes and gibibytes side by side. Showing one number and hiding the rest just means a second conversion a minute later.
The factors come from the defining agreements rather than from another converter. An inch is exactly 25.4 millimetres and a pound is exactly 0.45359237 kilograms, both fixed by international agreement in 1959, and a mile follows from the inch. Rounding those — 1.609 for a mile, say — is the usual way tools like this go quietly wrong, and it compounds every time somebody copies the answer.
Two distinctions are kept explicit because they are where people are most often misled. US and imperial gallons are different volumes, 3.785 litres against 4.546, and so are their pints and fluid ounces. And binary storage prefixes step by 1024 while decimal ones step by 1000, which is the entire reason a drive sold as 1 TB shows up as about 931 GiB.
- Ten measurement families, from length and temperature to digital storage and pressure
- Every unit of the family shown at once, each one ready to copy
- Factors taken from the defining agreements, not rounded from another site
- US and imperial volumes listed separately, because they are not the same size
- Binary and decimal storage prefixes kept apart and labelled
- Temperature handled on its own scale, so 0 °C is not treated as 0 °F
- Numbers grouped the way your language writes them
How to use it
- 1Pick the kind of measurement you are converting, such as length or temperature.
- 2Type the amount you have. The result updates as you type.
- 3Choose the unit you are converting from and the unit you want.
- 4Read the answer, or take any other unit from the table underneath.
- 5Use the swap button to reverse the direction without retyping anything.
Questions
Why does a 1 TB drive show as 931 GB on my computer?
The drive is sold in decimal terabytes (1000⁴ bytes) while your operating system reports binary tebibytes (1024⁴ bytes), often still labelled "GB". Both numbers are right and this converter lists the two separately so you can see the gap.
Are US and UK gallons the same?
No: a US gallon is 3.785 litres and an imperial gallon is 4.546, about 20% larger. Their pints and fluid ounces differ too, which is why both are listed and labelled here rather than offering one "gallon".
How accurate are these conversions?
The factors are exact where an exact definition exists — the inch, the pound, the nautical mile and the standard atmosphere are all defined precisely. Results are rounded to six significant figures for display, and the conversion always goes through the family base in one step so no rounding accumulates.
Why can I not convert kilograms to kilometres?
Because there is no number of kilograms that is a distance, so units only convert within their own family. The tool says so when a pair does not belong together rather than producing a meaningless figure.
What is a calorie on a food label?
It is a kilocalorie: 1000 small calories, or 4184 joules. Both are offered here and labelled, because treating a label calorie as a small calorie is wrong by a factor of a thousand.