Length Converter

Convert between meter, kilometer, mile, inch, foot, yard, and many other length and distance units with scientific precision.

Enter a number (e.g., 100 or 1.23e-4)
Enter a numeric value to convert. You can use decimal points and scientific notation (e.g., 1.23e-4). Press Enter to convert.
Result updates automatically
Copied!

Length Units Explained

Meter (m)

The SI base unit of length, defined as the distance light travels in vacuum in 1/299,792,458 second. The fundamental unit for all length measurements.

Common uses: Engineering, construction, general measurements, scientific calculations.

Kilometer (km)

One thousand meters. 1 km = 1,000 m. Used for large distances and geographic measurements.

Common uses: Road distances, geography, athletic events (5K, 10K), climate data.

Centimeter (cm)

One hundredth of a meter. 1 cm = 0.01 m. Common in everyday measurements and textbooks.

Common uses: Body measurements, clothing sizes, medical measurements, small objects.

Millimeter (mm)

One thousandth of a meter. 1 mm = 0.001 m. Used for precise measurements and small objects.

Common uses: Engineering drawings, precision manufacturing, jewelry, electronics.

Mile (mi)

Imperial unit of distance. 1 mi = 1.60934 km. Standard in USA, UK, and other countries.

Common uses: Road distances (US/UK), speed (miles per hour), geographic distances.

Foot (ft)

Imperial unit equal to 12 inches. 1 ft = 0.3048 m. Common in construction and real estate.

Common uses: Building dimensions, ceiling height, room size, athletics (track).

Inch (in)

Imperial unit, 1/12 of a foot. 1 in = 2.54 cm exactly. Common in US measurements.

Common uses: Clothing sizes, screen sizes (monitors, TVs, phones), manufacturing specifications.

Yard (yd)

Imperial unit equal to 3 feet. 1 yd = 0.9144 m. Used in textiles, sports, and construction.

Common uses: Fabric measurements, American football field, lawn area, landscaping.

Nanometer (nm)

One billionth of a meter. 1 nm = 10⁻⁹ m. Used in nanotechnology and atomic scale.

Common uses: Semiconductor transistor size, wavelength of visible light, protein size.

Micrometer (µm)

One millionth of a meter. 1 µm = 10⁻⁶ m = 0.001 mm. Used in precision manufacturing.

Common uses: Surface finish specifications, bacteria size, optical components, thin films.

Nautical Mile

Maritime unit based on Earth's circumference. 1 NM = 1.852 km. Used in navigation.

Common uses: Marine navigation, aviation, maritime law, sea distance measurements.

Light Year (ly)

Distance light travels in one year. 1 ly ≈ 9.461 trillion km. Used in astronomy.

Common uses: Astronomical distances, interstellar space, galaxy measurements.

Astronomical Unit (AU)

Average distance from Earth to Sun. 1 AU ≈ 149.6 million km. Used in solar system.

Common uses: Solar system distances, orbital measurements, planetary positions.

Angstrom (Å)

One ten-billionth of a meter. 1 Å = 10⁻¹⁰ m = 0.1 nm. Used in atomic physics.

Common uses: Atomic radius, wavelength of X-rays, crystal lattice spacing.

Length Conversion Quick Reference

  • 1 inch: Exactly 2.54 cm (defined)
  • 1 foot: 12 inches = 0.3048 m
  • 1 yard: 3 feet = 0.9144 m
  • 1 mile: 5,280 feet = 1.60934 km
  • 1 nautical mile: 1.852 km
  • 1 light year: 9.461 × 10¹² km
  • 1 parsec: 3.086 × 10¹³ km
  • Human height: Typically 150-190 cm
  • Room size: Typically 3-5 m on each side
  • Wavelength visible light: 380-700 nm