Length Unit Converter

Enter a length in any field and every other unit updates instantly across metric, imperial, U.S. customary, Chinese, nautical, astronomical, and printing systems.

Metric System

SI base units commonly used in science, engineering, and daily life.

Nanometers (nm)

Micrometers (µm)

Millimeters (mm)

Centimeters (cm)

Meters (m)

Kilometers (km)

Imperial System

International imperial units standardized in the United Kingdom and Commonwealth realms.

Thousandths of an Inch (thou)

Inches (in)

Feet (ft)

Yards (yd)

Chains (ch)

Miles (mi)

U.S. Customary System

Survey-oriented units used in the United States for land measurement.

U.S. Survey Feet (ft US)

U.S. Survey Yards (yd US)

U.S. Survey Chains (ch US)

U.S. Survey Miles (mi US)

Chinese Units (市制)

Modern decimalized Shìzhì units still used in select contexts.

Fen (分)

Cun (寸)

Chi (尺)

Zhang (丈)

Li (里)

Nautical Units

Marine navigation measures referenced to the Earth's circumference.

Fathoms (ftm)

Cable Lengths (cb)

Nautical Miles (NM)

Astronomical Units

Extremely large-scale measures used in astrophysics and cosmology.

Astronomical Units (AU)

Light Years (ly)

Parsecs (pc)

Printing & Typography Units

Fine-grained units used in typography, publishing, and graphic design.

Points (pt)

Picas (pc)

Twips (twip)

Agates (agate)

Tips for precise conversions

Use the mouse wheel or arrow keys over a field to nudge values and see proportional changes across all systems.
Very large or very small results automatically switch to scientific notation to preserve readability.
All conversions are calculated relative to the SI definition of the meter for maximum consistency.