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Length Converter

mm

cm

m

km

in

ft

ft/in

yd

mi

Common conversions
1 in = 2.54 cm · 1 ft = 0.3048 m · 1 m = 3.2808 ft · 1 mi = 1.6093 km

From cm to inches for a screen size to km to miles for a road trip, length is the conversion everyone needs eventually. This length converter takes one value and instantly shows it in all eight units — millimeters, centimeters, meters, kilometers, inches, feet, yards and miles.

How the conversions work

The meter is the SI base unit, and every other length is defined from it by an exact factor — these are international definitions, not approximations. One inch is exactly 2.54 cm, one foot exactly 0.3048 m, one yard exactly 0.9144 m, and one mile exactly 1,609.344 m. The converter multiplies your value to meters and back out to every unit, so results carry no rounding drift.

Everyday reference points

Handy anchors: 10 cm ≈ 4 inches; 30 cm is just under a foot; a meter is about 3.28 feet (a yard plus a hand-width); 5 km ≈ 3.1 miles (the classic fun-run); and 100 km ≈ 62 miles. For height, 170 cm is about 5'7" and 183 cm is 6'0".

Metric vs imperial in practice

Most of the world measures in metric; the US uses feet, inches and miles day-to-day, and the UK mixes both (miles on roads, metres elsewhere). If you work across both systems, remembering just two facts — 2.54 cm per inch and 1.609 km per mile — lets you sanity-check almost any conversion this tool gives you.

Related converters

For areas (square feet, acres, hectares) use the area converter — note area scales with the square of length. Converting how fast rather than how far? That's the speed converter. For kitchen volumes, see the cooking converter.

Frequently Asked Questions

How many centimeters are in an inch? +

Exactly 2.54 cm — an international definition, not an approximation. So 10 inches is 25.4 cm.

How do I convert feet to meters? +

Multiply feet by 0.3048 (exact). Ten feet is 3.048 m; going the other way, one meter is about 3.281 feet.

How many kilometers in a mile? +

One mile is exactly 1.609344 km. Quick estimates: 5 km ≈ 3.1 miles, 10 km ≈ 6.2 miles, 100 km ≈ 62 miles.

How do I convert my height to cm? +

Multiply feet by 30.48 and inches by 2.54, then add. For example 5'8" = 5×30.48 + 8×2.54 ≈ 172.7 cm.

How does the converter work? +

Every unit is defined relative to the meter by an exact factor, so your value converts once to meters and out to all eight units simultaneously with no rounding drift.

Are the conversion factors exact? +

Yes — inch, foot, yard and mile all have exact metric definitions fixed by international agreement in 1959 (1 in = 2.54 cm precisely).

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