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Unit Converter

Convert between units of length, weight, volume, speed, and area instantly. Select a category, enter a value, and see all conversions at once. No sign-up required.

0.001
Kilometer (km)
1 Meter (m)

All Length Conversions

Meter (m)1
Kilometer (km)0.001
Centimeter (cm)100
Millimeter (mm)1000
Mile (mi)0.000621371
Yard (yd)1.09361
Foot (ft)3.28084
Inch (in)39.3701
Nautical Mile (nmi)0.000539957

Most Common Unit Conversions

FromTo
1 mile1.60934 km
1 kg2.20462 lbs
1 liter0.26417 US gal
1 m/s3.6 km/h
1 foot0.3048 m
1 acre4,047 m²

The Metric vs. Imperial System

The metric system (SI) is used by most of the world. It is base-10: 1 kilometer = 1,000 meters, 1 kilogram = 1,000 grams. This makes calculations straightforward — just move the decimal point.

The imperial system is used primarily in the United States and, for some measures, the United Kingdom. It uses less intuitive ratios: 1 mile = 5,280 feet, 1 pound = 16 ounces. Converting between the two requires fixed multipliers.

Science, medicine, and international trade use metric universally. Everyday life in the US still uses imperial for speed (mph), distance (miles), and weight (lbs). This converter handles both, so you can work in whichever system you need.

Frequently Asked Questions

How do I convert miles to kilometers?▾
1 mile = 1.60934 kilometers. Multiply miles by 1.60934. Example: 10 miles = 16.0934 km. To go the other way, multiply km by 0.62137. This converter handles the calculation automatically.
How do I convert kilograms to pounds?▾
1 kilogram = 2.20462 pounds. Multiply kg by 2.20462. Example: 70 kg = 154.32 lbs. The reverse: divide pounds by 2.20462 (or multiply by 0.45359).
How do I convert liters to gallons?▾
1 US gallon = 3.78541 liters. To convert liters to US gallons, divide by 3.78541. Example: 10 liters = 2.642 US gallons. Note: the UK (Imperial) gallon is larger at 4.54609 liters. This tool uses US gallons.
What is a knot in mph?▾
1 knot = 1 nautical mile per hour = 1.15078 mph = 1.852 km/h. Knots are used in aviation and maritime navigation. A typical cruise speed for a commercial aircraft is 450–500 knots (~520–575 mph).
How many square feet in an acre?▾
1 acre = 43,560 square feet = 4,047 square meters = 0.4047 hectares. An acre is roughly the size of a football field (without end zones). 640 acres = 1 square mile.
What is the difference between mass and weight?▾
Mass is the amount of matter in an object (measured in kg, grams, lbs). Weight is the force gravity exerts on that mass (measured in Newtons). On Earth, mass and weight are proportional, so we commonly use "weight" to mean mass in everyday contexts. On the Moon, your mass stays the same but your weight is 1/6th of Earth weight.
How do I convert Celsius to Fahrenheit in a unit converter?▾
Temperature conversion requires a formula (not a simple multiplication factor), so it's handled by our dedicated Temperature Converter tool rather than this unit converter. Use that tool for °F, °C, and Kelvin conversions.