How our unit converters work
Every converter uses the official definition of each unit — for example, 1 inch is exactly 2.54 centimeters and 1 pound is exactly 0.45359237 kilograms — so results are exact and only rounded for display. Type in either box to convert in both directions, or use the swap button to reverse the units.
Metric vs imperial units
Most countries use the metric system (meters, kilograms, liters, Celsius). The United States mainly uses US customary units (feet, pounds, gallons, Fahrenheit), and the UK uses a mix — miles on road signs, stones for body weight and metric units in shops. These converters cover the conversions people need most when moving between the two systems.
US vs UK gallons and fluid ounces
Our volume converters use US units. A US gallon is 3.785 liters, while a UK (imperial) gallon is 4.546 liters. A US fluid ounce is 29.57 mL and a UK fluid ounce is 28.41 mL — check which one your recipe or product uses.
Decimal vs binary data sizes
Data size converters use decimal units (1 GB = 1,000 MB), the standard used by storage makers and mobile networks. Some operating systems count in binary (1 GB = 1,024 MB), which is why storage often looks smaller on a computer than on the box.