Unit Converter
Convert between US imperial and metric units — length, weight, volume and temperature — instantly.
What is this tool?
Americans live in inches, pounds and Fahrenheit while most of the world — and all of science — uses meters, kilograms and Celsius. This unit converter bridges the gap in both directions: recipe quantities from a European cookbook, a 180 lb weight limit stated in kilograms, highway distances in miles versus kilometers, or a 350°F oven temperature for a recipe written in Celsius.
Categories cover length (inches through miles and millimeters through kilometers), weight (ounces, pounds and US tons against grams and kilograms), volume (US fluid ounces, cups, pints and gallons against milliliters and liters), and temperature with the proper Fahrenheit–Celsius–Kelvin formulas rather than a simple ratio. Results update as you type.
How to use it
- Pick a category: length, weight, volume or temperature.
- Enter the value and choose the 'from' and 'to' units.
- Read the converted result — it updates instantly as you type.
Formula & method
Worked example
A traveler who weighs 180 lb is 81.6 kg. A 26.2-mile marathon is 42.16 kilometers. And a US recipe calling for 2 cups of milk needs about 473 milliliters — just under half a liter.
Frequently asked questions
How do I convert Fahrenheit to Celsius quickly?
Subtract 32, then multiply by 5/9. For a rough mental estimate, subtract 30 and halve the result: 86°F is about 28°C mentally and exactly 30°C. This converter gives the exact number.
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.785 liters; an imperial (UK) gallon is 4.546 liters — about 20 percent larger. This converter uses US gallons, the standard for American recipes, fuel and aquariums.
How many ounces are in a pound and a cup?
16 ounces by weight in a pound. A US cup is 8 fluid ounces by volume — but fluid ounces measure space, not weight, so a cup of flour does not weigh 8 ounces.