Length converter
Convert cm to inches, meters to feet, kilometers to miles, and more. Edit either side and the other updates instantly.
About the length converter
The length converter handles every common length unit in one place — centimeters, meters, kilometers, inches, feet, yards, and miles — plus less common ones like nautical miles, light-years, and parsecs. Use cm to inches for clothing and screen sizes, meters to feet for heights and building dimensions, km to miles for travel and running distances, and mm to inches for hardware and manufacturing specs. Edit either side and the other updates instantly — no "convert" button.
Centimeters to inches
One centimeter equals 0.3937 inches, and one inch equals exactly 2.54 centimeters. This is the most-searched length conversion because clothing, furniture, and screen sizes are often listed in inches in some markets and centimeters in others.
| cm | Inches | Feet + inches |
|---|---|---|
| 1 cm | 0.3937 in | — |
| 10 cm | 3.937 in | — |
| 30 cm | 11.811 in | — |
| 100 cm | 39.3701 in | 3 ft 3.37 in |
| 170 cm | 66.9291 in | 5 ft 6.93 in |
| 180 cm | 70.8661 in | 5 ft 10.87 in |
Meters to feet
One meter equals 3.2808 feet, and one foot equals exactly 0.3048 meters. This conversion comes up in architecture, building heights, pool lengths, and anywhere dimensions need to be communicated across the metric and imperial systems.
| m | Feet | Yards |
|---|---|---|
| 1 m | 3.2808 ft | 1.0936 yd |
| 5 m | 16.4042 ft | 5.4681 yd |
| 10 m | 32.8084 ft | 10.9361 yd |
| 25 m | 82.021 ft | 27.3403 yd |
| 50 m | 164.042 ft | 54.6807 yd |
| 100 m | 328.084 ft | 109.3613 yd |
Kilometers to miles
One kilometer equals 0.6214 miles, and one mile equals exactly 1.60934 kilometers. Most conversions used for travel distances, speed limits, and running events — a 5K run is 3.1 miles, a marathon is 26.2 miles or 42.2 km.
| km | Miles | Context |
|---|---|---|
| 1 km | 0.6214 mi | Short walk |
| 5 km | 3.1069 mi | 5K run |
| 10 km | 6.2137 mi | 10K run |
| 21.1 km | 13.1109 mi | Half marathon |
| 42.2 km | 26.2219 mi | Marathon |
| 100 km | 62.1371 mi | Long drive |
Millimeters to inches
One millimeter equals 0.0394 inches. This conversion matters most for hardware: screws, drill bits, hex keys, and camera lens filters. Outside the US, most screw specs are in millimeters; US tool catalogs use fractional inches. For quick reference: 3 mm is roughly 1/8 inch, 6 mm is roughly 1/4 inch, 25 mm is just under 1 inch.
How the conversion works
Every unit is defined relative to the meter, the SI base unit of length. To convert between any two units, the calculator multiplies by the source unit's meter factor and divides by the target unit's meter factor. The inch-to-meter ratio (0.0254) was fixed by the international yard and pound agreement of 1959. Because the ratios are exact SI-defined constants, the conversions are precise rather than approximate.