A length converter switches between metric units (millimetre, centimetre, metre, kilometre), imperial units (inch, foot, yard, mile), and nautical miles. The metre is the SI base unit — every other length is defined in terms of it.
What is Length Converter?
Length is the most fundamental measurement we deal with daily — height, distance, dimensions, height of a ceiling, length of a road, width of a screen. The world uses two main systems. Most countries use the metric system (metres), where conversions between units are simple powers of 10. The US still uses the imperial system (feet, inches, miles), where conversions are tied to historical references.
The SI definition of a metre is the distance light travels in vacuum in 1/299,792,458 of a second — about as precise as it gets. All other length units are now defined relative to the metre, including the inch (exactly 2.54 cm) and the foot (12 inches).
India is a metric country, but property dimensions are often quoted in feet, screen sizes in inches, and personal height in feet-and-inches. The calculator handles all the common cross-conversions instantly.
Conversion factors
Each unit has a fixed factor relative to the metre. Convert by multiplying to get to metres, then dividing by the target unit's factor.
- Source factor
- Source-to-metre—how many metres are in 1 source unit
- Target factor
- Target-to-metre—how many metres are in 1 target unit
How to use this calculator
Pick the source unit, the target unit, enter a value. Result updates instantly.
Enter the value
The number to convert. Decimals are fine — for height, use 1.78 for 1 m 78 cm.
Pick the source unit
What unit is the value currently in? mm, cm, m, km, in, ft, yd, mi, or nautical miles.
Pick the target unit
Which unit you want to convert to. Same set of options.
Common length conversions
Height in feet ↔ cm
5 ft 8 in = 173 cm. The standard medical record uses cm in India; passports and US visas often use feet-inches.
Property dimensions
1 acre = 43,560 sq ft. Plot sizes in India are usually quoted in square yards or square feet. Use this with the area converter.
Driving distance
Road signs in India use km; in the US they use miles. 100 km/h = 62 mph.
Marathon distance
42.195 km = 26.2 miles. Fitness trackers show one or the other.
Screen size
TV and phone screens are quoted in inches (diagonal). 55-inch TV diagonal = 139.7 cm.
Glossary
- Metre (m)
- SI base unit of length. About 3 ft 3 in. Defined by the speed of light.
- Foot (ft)
- Imperial unit equal to exactly 0.3048 m. 12 inches in a foot, 3 feet in a yard.
- Mile (mi)
- Imperial unit equal to 1.609344 km. Used for road distances in the US and UK.
- Nautical mile (nmi)
- Used in maritime and aviation navigation. Equals 1.852 km — based on one minute of latitude.