Length Converter

Q: Exact inch/foot conversions?

1 in = 25.4 mm exactly; 1 ft = 0.3048 m exactly.

Q: Why nautical miles?

Nautical miles are used in aviation and maritime contexts and equal 1852 m exactly.

Q: How big is a light-year?

1 light-year is 9.4607304725808 × 10^12 km (exact via defined speed of light and Julian year).

Q: Tips for entering values

Select the unit first, then enter a value once; all tiles update instantly.

Convert meters (m), kilometers (km), centimeters (cm), millimeters (mm), micrometers (µm), nanometers (nm), inches (in), feet (ft), yards (yd), miles (mi), nautical miles (nmi) and light-years (ly). Type in any unit; all others update instantly.

Meter

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FAQ

Exact inch/foot conversions?

By definition: 1 in = 25.4 mm exactly; 1 ft = 0.3048 m exactly.

Why nautical miles?

Nautical miles (nmi) are used in aviation and maritime contexts and equal 1852 m exactly.

How big is a light-year?

1 light-year is the distance light travels in a vacuum in one year: 9.460 730 472 580.8 km (exact via defined c and Julian year).

Tips for entering values

Select the unit first, then enter a value once — all tiles update instantly. Use scientific notation for very large/small values.