Length Converter

Convert between different units of length with precision. Support for metric, imperial, and US customary units.

Popular Conversions

Length Units

Millimeter (mm)
1/1000 of a meter, commonly used for precise measurements
Centimeter (cm)
1/100 of a meter, standard in metric system
Meter (m)
Base unit of length in the International System of Units (SI)
Kilometer (km)
1000 meters, used for measuring long distances
Inch (in)
Imperial unit, 1/12 of a foot, commonly used in US
Foot (ft)
Imperial unit, 12 inches, standard for height measurements

Conversion Tips

  • 1 meter = 100 centimeters = 1000 millimeters
  • 1 foot = 12 inches = 0.3048 meters (exactly)
  • 1 mile = 1.609344 kilometers (exactly)
  • 1 yard = 3 feet = 0.9144 meters (exactly)

Practical Examples

Construction: Room Dimensions

A bedroom measures 12 feet × 10 feet. Convert to meters:

12 ft = 3.6576 m
10 ft = 3.048 m
Area = 3.6576 × 3.048 = 11.15 m²

Sports: Track Length

A 400-meter track is how many yards?

400 meters = 437.445 yards
(Standard Olympic track length)

Engineering: Pipe Length

Convert 50 millimeters to inches for precision machining:

50 mm = 1.9685 inches
(Critical for pipe threading)

History of Length Measurement

Ancient Systems

The earliest length measurements were based on body parts: the cubit (elbow to fingertip), foot, and pace. Ancient Egyptians used the royal cubit of 52.4 cm for the pyramids.

The Metric System

Introduced in 1799 during the French Revolution, the meter was defined as one ten-millionth of the distance from the North Pole to the Equator. This system became the foundation for modern scientific measurement.

Modern Standards

Today, the meter is defined by the speed of light: 1 meter is the distance light travels in 1/299,792,458 seconds. This ensures unprecedented precision for scientific applications.

International Standards

The International System of Units (SI) defines seven base units, with the meter as the unit of length. All other length units are derived from this fundamental standard.

Common Applications

Architecture
Building plans, room dimensions
Navigation
Distance measurement, GPS
Engineering
Precision manufacturing, tolerances
Science
Laboratory measurements, research