Length Converter

How to Use the Length Converter

Type your value in the Value field, then select the unit you are converting from in the dropdown. The converter instantly shows the equivalent value in every other length unit — no Calculate button needed.

The selected unit is highlighted in blue so you always know your starting point. To start a new conversion, simply change the value or unit, or click Reset.

Length Units Explained

Length is the most fundamental physical dimension. The SI base unit is the meter (m). All metric units are decimal multiples or fractions of the meter.

Metric units

Nanometer (nm) — 0.000000001 m. Used in physics, chemistry, and semiconductor manufacturing.
Micrometer (μm) — 0.000001 m. Used to measure bacteria, cells, and fine tolerances.
Millimeter (mm) — 0.001 m. Everyday precision measurement (e.g., ruler markings).
Centimeter (cm) — 0.01 m. Common for body measurements and small objects.
Decimeter (dm) — 0.1 m. Less common; used in some European countries.
Meter (m) — the SI base unit.
Kilometer (km) — 1,000 m. Used for road distances in metric countries.

Imperial & US customary units

Inch (in) — 2.54 cm exactly.
Foot (ft) — 12 inches = 30.48 cm.
Yard (yd) — 3 feet = 91.44 cm.
Mile (mi) — 5,280 feet = 1,609.344 m.
Nautical mile (nmi) — 1,852 m. One minute of arc along a meridian; used in navigation.

Key Conversion Formulas

1 inch = 2.54 cm | 1 foot = 30.48 cm | 1 mile = 1,609.344 m | 1 nmi = 1,852 m

Worked Examples

Converting 5 feet 11 inches to centimeters

Convert to inches first: 5 × 12 + 11 = 71 inches. Then: 71 × 2.54 = 180.34 cm. This is a common height conversion.

Converting 100 meters to feet

100 m ÷ 0.3048 = 328.08 ft. The 100-meter sprint is about 109 yards.

Converting 42.195 km (marathon) to miles

42.195 km ÷ 1.609344 = 26.219 miles (26 miles 385 yards).

Converting 10 nautical miles to kilometers

10 × 1.852 = 18.52 km. A nautical mile covers exactly one arc-minute of latitude.

Frequently Asked Questions

How many centimeters are in an inch?

Exactly 2.54 cm. This is the international definition of the inch since 1959.

How many meters are in a mile?

One mile equals exactly 1,609.344 meters or approximately 1.609 km.

What is the difference between a mile and a nautical mile?

A statute mile is 1,609.344 m. A nautical mile is 1,852 m — about 15% longer. Nautical miles are used in aviation and maritime navigation because they correspond to one arc-minute of latitude.

How do I convert feet to meters?

Multiply feet by 0.3048. For example, 6 feet = 6 × 0.3048 = 1.8288 m.

How many inches are in a foot?

Exactly 12 inches. One yard equals 3 feet = 36 inches.

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