Length Conversion Calculator
Converts Metric, Imperial, Nautical, Astronomical, Chinese and Japanese units of measure
Length Measurement Calculator
Length Unit Converter
Select the unit of measurement that you know and enter its value. The calculator supports metric, imperial, nautical, astronomical, Chinese and Japanese units.
Length Units - Overview
SI System
1 m = 100 cm = 1,000 mm
Kilometer
1,000 m
≈ 0.621 mi
kmMile
1.609 km
≈ 1,609 m
miImportant Conversions
- 1 inch = 2.54 cm
- 1 foot = 30.48 cm = 12 inches
- 1 yard = 0.9144 m = 3 feet
- 1 mile = 1.609 km
- 1 nautical mile = 1.852 km
Metric System
The metric system with meter as base unit is standardized internationally (SI):
- 1 nm (nanometer) = 10⁻⁹ m
- 1 µm (micrometer) = 10⁻⁶ m
- 1 mm (millimeter) = 10⁻³ m
- 1 cm (centimeter) = 10⁻² m
- 1 m (meter) = base unit
- 1 km (kilometer) = 10³ m
Imperial System
The imperial system is mainly used in the USA and UK:
- 1 inch (in) = 2.54 cm
- 1 foot (ft) = 12 inches = 30.48 cm
- 1 yard (yd) = 3 feet = 0.9144 m
- 1 mile (mi) = 1,760 yards = 1.609 km
Nautical Units
Nautical mile (nmi) is used in shipping and aviation:
- 1 nmi = 1.852 km = 1,852 m
- Based on Earth's circumference
- 1' (arcminute) of latitude ≈ 1 nmi
Astronomical Units
Used for enormous distances in space:
- AU (Astronomical Unit): 149,597,870.7 km
Mean Earth-Sun distance - Light-year (ly): 9,460,730,472,580.8 km
Distance light travels in 1 Julian year - Parsec (pc): ≈ 3.26 light-years
≈ 30.857 trillion km
Common Units of Measure
At the international level, the metric system was established with the meter as the basis for length in the international system of units SI (Système international d'unités) to standardize the units of measurement. Nevertheless, other units are also used. The units of length mile, yard, foot and inch are mainly used in the Anglo-American. In astronomy, units such as light year, astronomical unit or parsec are used for calculations. The nautical units of measurement, nautical miles, are used in aviation and shipping.
Metric
The metric system with the meter as the base unit is the system of units for the length of a distance. In contrast to other systems, you can easily calculate with decimal multiples or fractions.
Anglo-American (Imperial) Units
The imperial units of length do not belong to the international system of units, so they are not SI-compliant. The mile is used, the length of which is 1.609344 kilometers. 1 yard is 3 feet and is 0.9144 meters in length. 1 foot is 30.48 centimeters which is the equivalent of 12 inches. 1 inch in turn corresponds to 2.54 cm.
Nautical Units
The nautical mile is a general one in shipping and aviation unit of measure used for length. It was precisely defined at 1,852.0 m.
Astronomical Units
These units of length are used in astronomy to describe the enormous proportions. They do not belong to the international system of units, but are indispensable for the description of distances in astronomy.
A light year is the distance that light travels in a year. The Julian year (365.25 days) was set as the basis for the definition of the light year. One light year is 9,460,730,472,580.8 km. The parsec corresponds to around 3.26 light years. The astronomical unit (AU) corresponds to the mean distance between the earth and the sun. By definition, it has a length of 149,597,870,700 meters.
Chinese Units
The Ancient Traditional Weights and Measures of China is parallel to the international system of units still in use in modern China. The standard of the system of units from the imperial time of China becomes Shìzhì called and was named at the beginning of the 20th century depending on the appropriate SI units redefined and used.
Japanese Units
Although trade has been limited to the use of the metric system since the beginning of the 20th century, old Japanese units of measurement are still used in some cases. The old measures are often found in carpentry and agriculture. The floor area is given in tatami mats and land is sold according to the price in tsubo.
Comparison Table
| Unit | Symbol | Equivalent in Meters | System |
|---|---|---|---|
| Meter | m | 1 | Metric |
| Kilometer | km | 1,000 | Metric |
| Inch | in | 0.0254 | Imperial |
| Foot | ft | 0.3048 | Imperial |
| Mile | mi | 1,609.344 | Imperial |
| Nautical Mile | nmi | 1,852 | Nautical |
| Astronomical Unit | AU | 149,597,870,700 | Astronomical |
| Light-year | ly | 9.46 × 10¹⁵ | Astronomical |
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