A length converter changes a distance from one unit into another — centimetres to inches, or kilometres to miles. It is handy whenever a measurement is given in a system you don't use day to day: reading an imperial tape measure in a metric country, sizing furniture from an overseas store, or comparing race distances. This tool covers metric units (mm, cm, m, km), imperial units (inch, foot, yard, mile) and the nautical mile.
The formula. Every value is converted through one base unit, the metre. Each unit has an exact factor: 1 inch = 2.54 cm, 1 foot = 0.3048 m, 1 yard = 0.9144 m, 1 mile = 1,609.344 m and 1 nautical mile = 1,852 m. A value is multiplied to metres, then divided by the target unit's factor: result = value × factor(from) ÷ factor(to).
Worked example. Say a room is 4.5 metres wide and you want the width in feet. Since 1 foot = 0.3048 m, divide: 4.5 ÷ 0.3048 ≈ 14.76 feet, or about 14 feet 9 inches. Going the other way, a 6-foot shelf is 6 × 0.3048 = 1.83 metres.
Where it's used. Length conversion comes up everywhere: a 5 km run is about 3.11 miles, a 55-inch TV is roughly 140 cm across, and an aircraft cruising at 35,000 feet is near 10,668 metres. Construction drawings, tailoring, shipping dimensions and international online shopping all mix metric and imperial units, so quick conversion avoids costly errors.