Length / Distance Converter

Most used length units

Popular length conversions

Centimeters to inches 1 cm = 0.3937008 in
Inches to centimeters 1 in = 2.54 cm
Meters to feet 1 m = 3.28084 ft
Feet to meters 1 ft = 0.3048 m
Kilometers to miles 1 km = 0.6213712 mi
Miles to kilometers 1 mi = 1.609344 km
Millimeters to inches 1 mm = 0.03937008 in
Inches to millimeters 1 in = 25.4 mm
Feet to inches 1 ft = 12 in
Inches to feet 1 in = 0.08333333 ft
Meters to yards 1 m = 1.093613 yd
Yards to meters 1 yd = 0.9144 m
Centimeters to feet 1 cm = 0.0328084 ft
Feet to centimeters 1 ft = 30.48 cm
Meters to centimeters 1 m = 100 cm
Centimeters to meters 1 cm = 0.01 m
Kilometers to meters 1 km = 1,000 m
Miles to feet 1 mi = 5,280 ft
Nautical miles to kilometers 1 nmi = 1.852 km
Light-years to kilometers 1 ly = 9,460,730,000,000 km
Micrometers to millimeters 1 µm = 0.001 mm
Nanometers to meters 1 nm = 1 × 10^-9 m
Yards to feet 1 yd = 3 ft
Millimeters to centimeters 1 mm = 0.1 cm

What is length?

Length is the measurement of how long something is from one end to the other; distance is the length of the path between two points. Both are measured with the same units, and length is one of the seven base quantities of the International System of Units (SI), whose base unit is the meter.

Most of the world uses the metric system, in which every length unit is the meter multiplied or divided by a power of ten: a kilometer is 1,000 meters and a millimeter is one thousandth of a meter. The United States, and the United Kingdom for road distances, still use inches, feet, yards and miles, which since 1959 have been defined exactly in terms of the meter (one inch is exactly 2.54 centimeters).

Science adds units for the very small, such as the ångström and the Bohr radius for atoms, and for the very large, such as the astronomical unit, the light-year and the parsec. Sailors and aviators use the nautical mile, and history has left hundreds of older units, from the Egyptian royal cubit to the Russian versta, which are still useful for reading old texts.

Metric and imperial length at a glance

1 inch = 2.54 cm exactly
1 foot = 12 inches = 30.48 cm
1 yard = 3 feet = 0.9144 m
1 mile = 1,760 yards = 1.609344 km
1 meter ≈ 3.28084 feet ≈ 39.3701 inches
1 kilometer ≈ 0.621371 miles
1 nautical mile = 1,852 m exactly ≈ 1.15078 miles

A short history of length measurement

The earliest length units came from the human body: the cubit (elbow to fingertip), the foot, the span of a hand and the width of a finger. Because bodies differ, every city and kingdom kept its own standards, and a "foot" could vary by several centimeters from one town to the next.

In 1793 revolutionary France defined the meter as one ten-millionth of the distance from the North Pole to the equator. A platinum bar made in 1799 became the reference, followed in 1889 by the international prototype meter kept near Paris. In 1960 the meter was redefined in terms of a wavelength of light from krypton-86, and since 1983 it has been defined as the distance light travels in a vacuum in 1/299,792,458 of a second, which ties length to time and the speed of light.

The international yard and pound agreement of 1959 fixed the yard at exactly 0.9144 m, which is why the inch is exactly 2.54 cm today. The older US survey foot, slightly longer, was retired at the end of 2022.

Length units from smallest to largest

Every proportional length unit on the site, ordered by size and expressed in meters.

Planck length 1.616255 × 10^-35 m
Femtometer 1 × 10^-15 m
Classical electron radius 2.81794 × 10^-15 m
X unit 1.0021 × 10^-13 m
Picometer 1 × 10^-12 m
Electron Compton wavelength 2.42631 × 10^-12 m
Bohr radius 5.291772 × 10^-11 m
ångström 1 × 10^-10 m
Nanometer 1 × 10^-9 m
Millimicron 1 × 10^-9 m
Beard-second 5 × 10^-9 m
Hu 3.333333 × 10^-7 m
Micrometer 0.000001 m
Si 0.00000333333 m
Thou 0.0000254 m
Mo 0.000030303 m
Hao 0.0000333333 m
Human hair width 0.000075 m
Punto 0.00016125 m
French point 0.000188 m
Tochka 0.000254 m
Japanese rin 0.00030303 m
Chinese li (small) 0.000333333 m
Millimeter 0.001 m
Linea 0.001935 m
Line 0.00211667 m
Ligne 0.0022558 m
Linha 0.0022917 m
Liniya 0.00254 m
Japanese bu 0.0030303 m
Korean bun 0.0030303 m
Chinese fen 0.00333333 m
Kraphiat 0.0052083 m
Grain of rice 0.006 m
Barleycorn 0.00846667 m
Centimeter 0.01 m
Shu-si 0.01667 m
Roman digit 0.0185 m
Egyptian digit 0.01875 m
Biblical finger 0.01875 m
Angul 0.01905 m
Greek finger 0.01927 m
Nio 0.0208333 m
Pulgada 0.02322 m
Roman inch 0.0247 m
Inch 0.0254 m
Dyuym 0.0254 m
US survey inch 0.0254001 m
Duim 0.0257 m
Prussian inch 0.026154 m
Pouce 0.02707 m
Polegada 0.0275 m
Sun 0.030303 m
Korean chi 0.030303 m
Attoparsec 0.0308568 m
Paperclip length 0.033 m
Cun 0.0333333 m
Kondylos 0.03854 m
Vershok 0.04445 m
Nail 0.05715 m
Roman palm 0.074 m
Egyptian palm 0.075 m
Handbreadth 0.075 m
Palm 0.0762 m
Greek palm 0.07708 m
Credit card length 0.0856 m
Decimeter 0.1 m
Hand 0.1016 m
Finger 0.1143 m
Smartphone length 0.15 m
Shaftment 0.1524 m
Dichas 0.15415 m
Pyad 0.1778 m
Banana 0.18 m
Pencil length 0.19 m
Link 0.201168 m
Palmo 0.22 m
Biblical span 0.225 m
Span 0.2286 m
Greek span 0.23123 m
Khuep 0.25 m
Castilian foot 0.278635 m
Roman foot 0.296 m
Shaku 0.30303 m
Ja 0.30303 m
Foot 0.3048 m
Russian foot 0.3048 m
US survey foot 0.304801 m
Greek foot 0.3083 m
Prussian foot 0.31385 m
Pied du roi 0.324841 m
Portuguese foot 0.33 m
Chi 0.333333 m
Pygme 0.34684 m
Remen 0.37 m
Kujirajaku 0.378788 m
Roman cubit 0.444 m
Egyptian common cubit 0.45 m
Biblical cubit 0.45 m
Cubit 0.4572 m
Hasta 0.4572 m
Greek cubit 0.46245 m
Dhira 0.4933 m
Kush 0.5 m
Sok 0.5 m
Royal cubit 0.525 m
Aln 0.5938 m
Prussian ell 0.6669 m
Arshin 0.7112 m
Roman step 0.74 m
Arsin 0.758 m
Bema 0.77075 m
Castilian vara 0.835905 m
Mexican vara 0.838 m
Texas vara 0.846667 m
Yard 0.9144 m
Gaj 0.9144 m
Meter 1 m
Portuguese vara 1.1 m
Ell 1.143 m
Aune 1.188 m
Spanish pace 1.3932 m
Roman pace 1.48 m
Chinese bu 1.66667 m
Human height 1.7 m
Smoot 1.7018 m
Famn 1.781 m
Ken 1.81818 m
Fathom 1.8288 m
Danda 1.8288 m
Orgyia 1.8498 m
Toise 1.949 m
Wa 2 m
Sazhen 2.1336 m
Braca 2.2 m
Reed 2.7 m
Jo 3.0303 m
Zhang 3.33333 m
Qasaba 3.696 m
Prussian rod 3.766 m
Rhineland rod 3.767 m
Rod 5.0292 m
Giraffe height 5.5 m
Nindan 6 m
Decameter 10 m
Double-decker bus 11 m
Chain 20.1168 m
Blue whale length 25 m
Shackle 27.432 m
Ramsden's chain 30.48 m
Plethron 30.83 m
Yin 33.3333 m
Sen 40 m
Olympic pool length 50 m
Khet 52.5 m
American football field 91.44 m
Statue of Liberty height 93 m
Hectometer 100 m
Soccer pitch length 105 m
Cho 109.091 m
Roman stadium 185 m
Stadion 185 m
Cable 185.2 m
Furlong 201.168 m
Eiffel Tower height 330 m
Ush 360 m
Diaulos 370 m
Empire State Building height 381 m
Korean ri 392.7 m
Chinese li 500 m
Hippikon 740 m
Burj Khalifa height 828 m
Sabbath day's journey 900 m
Talmudic mil 960 m
Kilometer 1,000 m
Versta 1,066.8 m
Sheppey 1,408.18 m
Roman mile 1,480 m
Mile 1,609.34 m
US survey mile 1,609.35 m
Scottish mile 1,814.2 m
Nautical mile 1,852 m
Admiralty mile 1,853.18 m
Irish mile 2,048.3 m
Gallic league 2,220 m
Fjardingsvag 2,672 m
Kos 3,218.69 m
Biblical parasang 3,840 m
Japanese ri 3,927.27 m
Lieue 4,444.8 m
Swiss hour 4,800 m
League 4,828.03 m
Welsh mile 5,486.4 m
Parasang 5,550 m
Nautical league 5,556 m
Spanish league 5,572.7 m
Farsakh 5,760 m
Legua 6,600 m
Russian mile 7,467.6 m
Prussian mile 7,532.5 m
Danish mile 7,532.5 m
Mount Everest height 8,848.86 m
Swedish mil 10,000 m
Iteru 10,500 m
Beru 10,800 m
Yojana 12,874.8 m
Yot 16,000 m
Barid 23,040 m
Day's journey 38,400 m
Marathon 42,195 m
Megameter 1,000,000 m
Earth radius 6,371,000 m
Earth diameter 12,742,000 m
Earth circumference 40,075,000 m
Jupiter radius 71,492,000 m
Light-second 299,792,000 m
Lunar distance 384,399,000 m
Solar radius 695,700,000 m
Gigameter 1,000,000,000 m
Light-minute 17,987,500,000 m
Astronomical unit 149,598,000,000 m
Light-hour 1,079,250,000,000 m
Light-day 25,902,100,000,000 m
Light-week 181,314,000,000,000 m
Light-year 9.46073 × 10¹⁵ m
Parsec 3.085678 × 10¹⁶ m
Siriometer 1.495979 × 10¹⁷ m
Kiloparsec 3.085678 × 10¹⁹ m
Megaparsec 3.085678 × 10²² m
Gigaparsec 3.085678 × 10²⁵ m
Hubble length 1.3216 × 10²⁶ m

All 231 length units

Metric (SI)

Imperial & US customary

US survey

Nautical

Astronomical

Scientific & atomic

Ancient

East & Southeast Asian

South Asian & Middle Eastern

European (pre-metric)

Spanish & Portuguese

Everyday comparisons

Frequently asked questions

What is the SI unit of length?

The meter (m). It is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.

How many centimeters are in an inch?

Exactly 2.54 centimeters. The inch has been defined this way since the 1959 international yard and pound agreement.

How many feet are in a meter?

One meter is about 3.28084 feet, or 3 feet 3.37 inches.

Is a kilometer longer than a mile?

No. A mile is 1.609344 kilometers, so a kilometer is only about 0.621 miles.

What is the difference between a mile and a nautical mile?

A statute mile is 1,609.344 m. A nautical mile is 1,852 m, based on one minute of latitude, and is used at sea and in aviation.