Unit Converter

What is unit converter?

A unit converter changes a measurement from one unit to another, such as miles to kilometers, pounds to kilograms or gallons to liters. It is useful for cooking, travel, shopping, school work and international business.

Because every result is shown in all units of the category, you can also scan the table to find the unit you need without a second search.

How to use the unit converter

1. Select the category.
2. Choose the From and To units from the lists and enter the value.
3. Press Calculate to see the answer and the full table.

How the unit converter works

Each unit is stored as a multiple of one base unit, such as the meter for length or the kilogram for weight. Your value is converted to the base unit and then to the target unit. Factors follow internationally agreed definitions, for example 1 mile is exactly 1,609.344 meters.

Worked example

Common uses of the unit converter

• Following a recipe written in cups, ounces or gallons.
• Reading a product spec in miles, pounds or square feet.
• Converting fuel economy and distances for travel abroad.
• Checking homework in science and engineering.
• Comparing data sizes such as megabytes and gigabytes.

Tips and common mistakes

US and UK gallons, pints and cups are different sizes. Choose the correct one for your recipe or fuel receipt.

Digital data here uses 1,024 as the step (binary), which is how operating systems usually report file sizes.

Background: what to know before you rely on it

Two big systems of measurement exist today. The metric system, built on tens, is used by almost every country. The imperial and US customary systems survive in the United States, and in daily life in the United Kingdom for things like miles and pints. Units with the same name can differ: a US gallon is smaller than a UK gallon, and a US fluid ounce differs slightly from the UK one. In computing, a kilobyte is 1,000 bytes to disk makers but 1,024 bytes to many operating systems. Knowing which convention is in use avoids costly mistakes. In 1999 NASA lost the Mars Climate Orbiter after one team used imperial units and another used metric.

Private, free and fast

This tool runs entirely in your browser. What you type or choose is not uploaded to a server and is not saved after you close the page, which keeps it fast and private. It is free to use as often as you like. See more in all converters, or browse the full list of tools.

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Results are for information and education. For legal, financial, medical or security decisions, check with a qualified professional. Check critical conversions with an official source.