Length converter
Convert length units instantly — meters, feet, inches, miles, kilometers, centimeters, and more. Metric and imperial.
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Common length units
Meter (m)
Definition: The meter (symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, it is formally defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second.
History/origin: The meter was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along the meridian through Paris. Over the centuries the definition was refined multiple times: first tied to a physical platinum-iridium bar, then to the wavelength of light, and finally to the speed of light.
Current use: The meter is the primary unit of length in virtually every country in the world. It is used in science, engineering, construction, and everyday measurement everywhere the metric system has been adopted.
Kilometer (km)
Definition: A kilometer (symbol: km) is equal to 1,000 meters. It is a unit of length in the SI system derived from the base unit meter using the prefix "kilo-", which denotes a factor of 1,000.
History/origin: The kilometer emerged alongside the metric system in France in the late 18th century. As trade and travel expanded, a larger practical unit of distance was needed beyond the meter, making the kilometer a natural and convenient choice.
Current use: Kilometers are widely used to express distances between geographic locations in most countries that use the metric system. Road signs, maps, and navigation systems in Europe, Asia, Africa, and most of the Americas display distances in kilometers.
Inch (in)
Definition: An inch (symbol: in or ") is a unit of length in the imperial and US customary systems of measurement. Since 1959, one inch has been defined as exactly 25.4 millimeters. There are 12 inches in a foot and 36 inches in a yard.
History/origin: The word "inch" derives from the Latin "uncia", meaning one-twelfth. Early definitions were based on natural references: the width of a human thumb or the length of three barleycorns placed end to end. The modern standardized definition was agreed upon internationally in 1959.
Current use: The inch remains in common use in the United States, Canada, and the United Kingdom, particularly for human height, screen sizes, and construction materials such as lumber and pipes.
Foot (ft)
Definition: A foot (symbol: ft or ') is a unit of length equal to exactly 0.3048 meters, or 12 inches. It is part of the imperial and US customary systems of measurement.
History/origin: As the name suggests, the foot was historically based on the length of a human foot. Various cultures used their own versions of the foot as a practical unit of measure. The international foot was standardized at exactly 0.3048 m in 1959.
Current use: The foot is primarily used in the United States for altitude in aviation, human height, and real estate. It also remains in common use in the United Kingdom alongside metric units.
Mile (mi)
Definition: A mile (symbol: mi) is a unit of length equal to exactly 1,609.344 meters or 5,280 feet. It is used in the imperial and US customary measurement systems.
History/origin: The mile originates from the Roman "mille passuum" (a thousand paces), which was approximately 1,480 meters. Over time the English mile evolved to its current standardized length, fixed at 1,609.344 m in 1959 alongside the international yard and foot agreement.
Current use: Miles are used for road distances in the United States, United Kingdom, and a handful of other countries. Speed limits, odometers, and road signs in these regions display distances in miles rather than kilometers.
Length conversion table
| From | To | Result |
|---|---|---|
| 1 Centimeter (cm) | Inches (in) | 0.3937 in |
| 1 Inch (in) | Centimeters (cm) | 2.54 cm |
| 1 Meter (m) | Feet (ft) | 3.2808 ft |
| 1 Foot (ft) | Meters (m) | 0.3048 m |
| 1 Kilometer (km) | Miles (mi) | 0.6214 mi |
| 1 Mile (mi) | Kilometers (km) | 1.6093 km |
| 1 Meter (m) | Yards (yd) | 1.0936 yd |
| 1 Yard (yd) | Meters (m) | 0.9144 m |
| 1 Foot (ft) | Centimeters (cm) | 30.48 cm |
| 1 Mile (mi) | Meters (m) | 1609.344 m |
How to convert length units
Most length conversions follow a simple multiplication by a fixed factor. To convert from one unit to another, multiply the value by the ratio between the two units.
Centimeters to inches
inches = centimeters × 0.3937007874
Example: 30 cm = 30 × 0.3937007874 = 11.811 in
Kilometers to miles
miles = kilometers × 0.6213711922
Example: 10 km = 10 × 0.6213711922 = 6.2137 mi
Meters to feet
feet = meters × 3.280839895
Example: 5 m = 5 × 3.280839895 = 16.404 ft
Frequently asked questions
How do I convert centimeters to inches?
Multiply the centimeter value by 0.3937. For example, 30 cm = 30 × 0.3937 = 11.81 inches. To go the other direction, multiply inches by 2.54. One inch is exactly 2.54 cm — this has been the international standard since 1959.
How do I convert kilometres to miles?
Multiply kilometres by 0.6214. For example, 10 km = 6.214 miles. To convert miles to kilometres, multiply by 1.6093. A quick mental shortcut: multiply km by 0.6 for a rough miles figure — 5 km ≈ 3 miles, 100 km ≈ 62 miles.
How many feet are in a meter?
One meter equals approximately 3.2808 feet. One foot equals exactly 0.3048 meters. For quick estimates: 1 metre ≈ 3 feet 3 inches, 2 metres ≈ 6 feet 7 inches, 1.8 metres ≈ 5 feet 11 inches (a common height reference).
How do I convert height from cm to feet and inches?
Divide the centimeter value by 2.54 to get total inches, then divide by 12 to get feet and take the remainder as inches. For example, 175 cm ÷ 2.54 = 68.9 inches = 5 feet 8.9 inches. Common reference points: 160 cm = 5'3", 170 cm = 5'7", 180 cm = 5'11", 190 cm = 6'3".
How many inches are in a foot?
There are exactly 12 inches in one foot. There are 3 feet in one yard, and 5,280 feet in one mile. These are exact definitions in the imperial and US customary systems.
How do I convert miles to kilometers?
Multiply miles by 1.60934. For example, 26.2 miles (a marathon) = 26.2 × 1.60934 = 42.16 km. To convert km to miles, multiply by 0.6214. Speed limits in miles per hour (mph) can be converted to km/h using the same factor: 60 mph = 96.56 km/h.
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