Length Converter

Length conversion is the most common unit conversion in daily life — heights, distances, fabric, screen sizes, furniture. This length converter translates instantly between millimeters, centimeters, meters, kilometers, inches, feet, yards and miles using exact international definitions.

Since 1959 the inch is defined as exactly 25.4 mm, so every conversion here is exact, not an approximation.

Enter valid values to see the results.

Formula

Result = Value × (from-unit in meters) ÷ (to-unit in meters)

Every unit is defined through meters: 1 in = 0.0254 m exactly, 1 ft = 0.3048 m, 1 yd = 0.9144 m, 1 mi = 1609.344 m. Converting via the base unit avoids compounding rounding errors.

What you need

Enter the value, pick the unit you have (“From”) and the unit you need (“To”).
The result updates instantly; the second line shows the unit rate, e.g. 1 m = 3.28084 ft.
Negative values and decimals are supported for temperature-style offsets and precise work.

Worked example

Convert 100 m to feet: 100 × 1 ÷ 0.3048 = 328.084 ft. And a 6 ft person is 6 × 0.3048 = 1.8288 m tall — about 183 cm.

Practical tips

Memorize three anchors: 1 in = 2.54 cm, 1 m ≈ 3.28 ft, 1 mi ≈ 1.61 km — most everyday conversions are near these.
For quick mental math, 8 km ≈ 5 miles; multiply or divide by 1.6 for better precision.
Screen sizes and plumbing use inches even in metric countries — keep this converter handy when shopping internationally.
Feet-and-inches notation (5′11″) means 5 × 12 + 11 = 71 inches = 180.3 cm.

Length conversion quick reference

Unit	In meters	Common use
1 inch	0.0254 m	Screens, pipes
1 foot	0.3048 m	Height, rooms
1 yard	0.9144 m	Fabric, sports fields
1 mile	1609.344 m	Road distances

Common mistakes

1 Confusing US survey feet with international feet in old land records — the difference is tiny (2 ppm) but real in surveying.
2 Mixing up miles and nautical miles: 1 nautical mile = 1.852 km, used in aviation and shipping.
3 Rounding conversion factors too early — 1 ft ≈ 0.3 m introduces 1.6% error.

Frequently asked questions

How many centimeters are in an inch?

Exactly 2.54 cm — this is the international definition since 1959, not an approximation.

How do I convert meters to feet?

Multiply meters by 3.28084. For a rough figure, multiply by 3.3 (about 0.6% high).

How many kilometers are in a mile?

1 mile = 1.609344 km exactly. Going the other way, 1 km = 0.621371 miles.

What is the difference between a yard and a meter?

A meter is about 9.4% longer: 1 m = 1.0936 yd, and 1 yd = 0.9144 m.