Unit Converter
Length, weight, temperature, volume, and speed — convert between any units instantly.
A single converter for the units people look up every day: metres, feet, kilograms, pounds, Celsius, Fahrenheit, litres, gallons, and more. Pick a category, pick your units, and the result updates as you type.
Units covered
- Length: millimeters, centimeters, meters, kilometers, inches, feet, yards, miles
- Weight: milligrams, grams, kilograms, metric tons, ounces, pounds, stone
- Area: square centimeters, square meters, hectares, square kilometers, square feet, square yards, acres — for a dedicated version see the area converter.
- Volume: milliliters, liters, cups, pints, quarts, gallons, cubic meters
- Speed: meters/second, kilometers/hour, miles/hour, knots
- Temperature: Celsius, Fahrenheit, Kelvin
US to metric quick reference
The US customary system is used for most everyday measurements in the United States, while almost everywhere else — and most science, medicine and product labels — uses metric. These are the conversions people look up most:
| US unit | Metric | Metric | US unit |
|---|---|---|---|
| 1 inch | 2.54 cm | 1 cm | 0.3937 in |
| 1 foot | 30.48 cm | 1 meter | 3.2808 ft |
| 1 mile | 1.6093 km | 1 km | 0.6214 mi |
| 1 pound | 0.4536 kg | 1 kg | 2.2046 lb |
| 1 ounce | 28.35 g | 100 g | 3.527 oz |
| 1 US gallon | 3.7854 L | 1 liter | 1.0567 qt |
| 1 US cup | 236.6 mL | 1 hectare | 2.471 acres |
Everyday examples
- Driving: a 65 mph speed limit is about 104.6 km/h, and a 100 km/h sign abroad is about 62.1 mph.
- Running: a 5K race is 3.11 miles and a 26.2-mile marathon is 42.2 km.
- Cooking: an oven at 350°F is about 176.7°C, which recipes usually round to 175 or 180°C.
- Weather and health: 0°C is 32°F, 100°C is 212°F, and a body temperature of 98.6°F is 37°C.
- Land: one acre is exactly 43,560 square feet, or about 4,047 m².
US vs. imperial units
US and British (imperial) volume units share names but not sizes. A US gallon is 3.785 liters, while an imperial gallon is about 4.546 liters, and the same goes for pints and fluid ounces. This converter uses US measures for cups, pints, quarts and gallons. Length and weight units — inches, feet, miles, ounces and pounds — are the same in both systems.
Frequently asked questions
Does the conversion happen on a server?
No — every conversion runs instantly in your browser using plain JavaScript. Nothing you type is sent anywhere.
How accurate are the results?
Conversions use the internationally defined exact factors (for example, 1 inch = 2.54 cm exactly), so results are accurate to 8 decimal places before rounding for display.
Can I convert in the other direction?
Yes — type into either the "From" or the "To" field and the other side updates automatically, or use the swap button to flip both sides at once.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. For example, 68°F − 32 = 36, and 36 × 5/9 = 20°C. To go from Celsius to Fahrenheit, multiply by 9/5 and add 32.
How many pounds are in a kilogram?
One kilogram is about 2.2046 pounds. The pound is defined as exactly 0.45359237 kg, so 70 kg is about 154.3 lb.
Why does the US still use feet, pounds and gallons?
The US customary system was in place long before metric spread, and switching road signs, building codes and packaging is costly. US units are officially defined in metric terms, though — an inch is exactly 2.54 cm by law.