Length Converter — Convert mm, cm, m, km, in, ft, yd, mi
Enter a length value, pick your unit, and see all other units instantly with the formula shown.
Length is the most common physical measurement, yet unit systems vary by region and discipline. Metric uses base-10 steps — millimeters to centimeters to meters to kilometers — while the US customary system uses inches, feet, yards, and miles with less tidy ratios. This converter covers all eight units used in everyday life, engineering, and navigation. Enter any value, pick your starting unit, and every other unit updates instantly with the exact conversion formula.
How to use the length converter
- Enter the length value you want to convert.
- Select the unit you are converting from using the dropdown.
- The tool shows all other units at once with the formula for each.
- Click Copy next to any result to copy it to your clipboard.
- Share a specific conversion by copying the URL — it preserves your value and unit.
Worked examples
ft to m: person's height
Enter 6 and select foot. Formula: 6 times 0.3048 equals 1.8288 m. A person who is 6 ft tall is exactly 182.88 cm — often rounded to 183 cm.
km to mi: marathon distance
Enter 42.195 and select kilometer. Formula: 42.195 times 0.62137 equals 26.219 mi. The official marathon distance is 42.195 km, equivalent to 26 miles and 385 yards.
in to cm: screen size
Enter 15.6 and select inch. Formula: 15.6 times 2.54 equals 39.624 cm. A 15.6-inch laptop screen has a diagonal of 39.6 cm.
m to yd: swimming pool
Enter 50 and select meter. Formula: 50 times 1.0936 equals 54.680 yd. An Olympic swimming pool is 50 m, or about 54.7 yards.
Conversion factor reference
| From | To | Formula |
|---|---|---|
| m | ft | multiply by 3.2808 |
| ft | m | multiply by 0.3048 |
| m | in | multiply by 39.370 |
| in | m | multiply by 0.025400 |
| km | mi | multiply by 0.62137 |
| mi | km | multiply by 1.6093 |
| m | yd | multiply by 1.0936 |
| yd | m | multiply by 0.91440 |
| ft | in | multiply by 12 |
| in | ft | multiply by 0.083333 |
| ft | yd | multiply by 0.33333 |
| yd | ft | multiply by 3 |
| mi | ft | multiply by 5280 |
| km | m | multiply by 1000 |
| cm | in | multiply by 0.39370 |
| mm | in | multiply by 0.039370 |
Real-world length reference
| Object / Distance | Metric | Imperial |
|---|---|---|
| Credit card width | 85.6 mm | 3.370 in |
| A4 paper (long side) | 297 mm | 11.69 in |
| Standard door height | 2 m | 6.562 ft |
| Basketball court length | 28 m | 91.86 ft |
| 1 city block (approx) | 80 m | 87.49 yd |
| Eiffel Tower height | 330 m | 1082.7 ft |
| English Channel width (narrowest) | 33.3 km | 20.70 mi |
| Earth diameter | 12,742 km | 7917.5 mi |
Frequently asked questions
How do you convert feet to meters?
Multiply the length in feet by 0.3048 to get meters. For example, 6 ft times 0.3048 equals 1.8288 m. The conversion is exact: 1 foot is defined as exactly 0.3048 meters.
How do you convert inches to centimeters?
Multiply the length in inches by 2.54 to get centimeters. For example, 12 in times 2.54 equals 30.48 cm. This is an exact definition: 1 inch equals exactly 2.54 centimeters.
How do you convert kilometers to miles?
Multiply the length in kilometers by 0.62137 to get miles. For example, 10 km times 0.62137 equals 6.2137 mi. Alternatively, divide by 1.60934.
How many feet are in a mile?
There are exactly 5,280 feet in one mile. This is a fixed definition in the US customary and imperial systems. In metric, 1 mile equals exactly 1,609.344 meters.
How do you convert meters to yards?
Multiply the length in meters by 1.09361 to get yards. For example, 100 m times 1.09361 equals 109.361 yd. This derives from 1 yard equaling exactly 0.9144 meters.
How many centimeters are in an inch?
There are exactly 2.54 centimeters in one inch. This is an internationally agreed exact definition. So 1 inch equals 2.54 cm, and 1 cm equals about 0.39370 inches.
How do you convert millimeters to inches?
Divide the length in millimeters by 25.4 to get inches. For example, 100 mm divided by 25.4 equals 3.9370 in. This is exact: 1 inch = 25.4 mm by definition.
How accurate are these length conversions?
Results are shown to at least 5 significant figures using exact conversion factors. All imperial factors derive from exact SI definitions: 1 inch = 0.0254 m, 1 foot = 0.3048 m, 1 yard = 0.9144 m, and 1 mile = 1,609.344 m.
What is the difference between yards and meters?
One yard equals 0.9144 meters, so a meter is slightly longer than a yard (about 9.36% longer). A 100-yard American football field is about 91.44 meters.