List of examples of lengths

Planets of the Solar System to scale

This is a list of examples of lengths, in metres in order to give an understanding of lengths.

Shorter than 1 ym

• 6965162000000000000♠1.62×10⁻³⁵ metres = the Planck length

1 ym to 1 zm

• 6976099999999999999♠1×10⁻²⁴ metres = 1 ym = 1 yoctometre, the smallest named subdivision of the metre in the SI base unit of length.
• 6977099999999999999♠1×10⁻²³ metres = 10 ym
• 6977199999999999999♠2×10⁻²³ metres = 20 ym, the effective cross-section radius of 1 MeV neutrinos as measured by Clyde Cowan and Frederick Reines^[1]

1 zm to 1 am

• 6979099999999999999♠1×10⁻²¹ metres = 1 zm = 1 zeptometre = 7003100000000000000♠1000 yoctometres
• 6979199999999999999♠2×10⁻²¹ metres = radius of effective cross section for a 20 GeV neutrino scattering off a nucleon^[2]
• 6979699999999999999♠7×10⁻²¹ metres = radius of effective cross section for a 250 GeV neutrino scattering off a nucleon^[2]
• 6980099999999999999♠1×10⁻²⁰ metres = 10 zm
• 6981099999999999999♠1×10⁻¹⁹ metres = 100 zm
• 310 zm — de Broglie wavelength of protons at the Large Hadron Collider (4 TeV as of 2012)

1 am to 1 fm

• 6982100000000000000♠1×10⁻¹⁸ metres = 1 am = 1 attometre = 7003100000000000000♠1000 zeptometres
• 1 am — sensitivity of the LIGO detector for gravitational waves
• 6983100000000000000♠1×10⁻¹⁷ metres = 10 am
• 6984100000000000000♠1×10⁻¹⁶ metres = 100 am
• 0.85 fm — approximate proton radius^[3]

1 fm to 1 pm

• 6985100000000000000♠1×10⁻¹⁵ metres = 1 fm = 1 femtometre = 7003100000000000000♠1000 attometres
• 1.5 fm — diameter of the Scattering Cross Section of an 11 MeV proton with a target proton^[4]
• 6985281794000000000♠2.81794 fm — classical electron radius^[5]
• 7 fm - the radius of the effective scattering cross section for a gold nucleus scattering a 6 MeV alpha particle over 140 degrees^[4]
• 6986100000000000000♠1×10⁻¹⁴ metres = 10 fm
• 6987100000000000000♠1×10⁻¹³ metres = 100 fm
• 6988100000000000000♠1×10⁻¹² metres = 1 pm = 1 picometre = 7003100000000000000♠1000 femtometres

1 picometre

Lengths between 10⁻¹² and 10⁻¹¹ m (1 and 10 pm).

• 1 pm = 1 picometre = 7003100000000000000♠1000 femtometres
• 1 pm = distance between atomic nuclei in a white dwarf star
• 2.4 pm — The Compton wavelength of the electron.
• 5 pm — shorter X-ray wavelengths (approx.)

10 picometres

Lengths between 10⁻¹¹ and 10⁻¹⁰ m (10 pm and 100 pm).

• 25 pm — empirical radius of hydrogen atom^[6]
• 28 pm — covalent radius of helium atom^[7]
• 31 pm — covalent radius of hydrogen atom^[6]
• 31 pm — calculated radius of helium atom^[7]
• ~50 pm — best resolution of a high-resolution transmission electron microscope^[8]
• 53 pm — calculated radius of hydrogen atom^[6]

100 picometres

lengths between 10⁻¹⁰ and 10⁻⁹ m (100 pm and 1 nm).

• 100 pm — 1 angstrom
• 100 pm — covalent radius of sulfur atom^[9]
• 120 pm — van der Waals radius of a neutral hydrogen atom^[10]
• 126 pm — covalent radius of ruthenium atom
• 135 pm — covalent radius of technetium atom
• 153 pm — covalent radius of silver atom
• 154 pm — mode length of (C-C) covalent bond
• 155 pm — covalent radius of zirconium atom
• 175 pm — covalent radius of thulium atom
• 200 pm — highest resolution of a typical electron microscope^[11]
• 225 pm — covalent radius of caesium atom
• 340 pm — thickness of single layer graphene
• 356.68 pm — width of diamond cell (unit cell)
• 403 pm — width of lithium fluoride cell
• 500 pm — width of α helix protein
• 560 pm — width of sodium chloride cell
• 700 pm — width of glucose molecule
• 780 pm — mean width of quartz cell
• 820 pm — mean width of ice cell
• 900 pm — mean width of coesite cell
• 900 pm — width of sucrose molecule

10 nanometres 1x10⁻⁹m

Comparison of sizes of semiconductor manufacturing process nodes with some microscopic objects and visible light wavelengths. At this scale, the width of a human hair is about 10 times that of the image.^[12]

To help compare different orders of magnitude this page lists lengths between 10⁻⁸ and 10⁻⁷ m (10 and 100 nm).

• 10 nm = 10 nanometres = 10⁻⁸ metres
• 10 nm — lower size of tobacco smoke^[13]
• 10 nm Shortest extreme ultraviolet wavelength or longest X-ray wavelength^[14]
• 11 nm — the average half-pitch of a memory cell speculated to be manufactured in 2015.
• 16 nm — technology is projected to be reached by semiconductor companies in the 2013 timeframe
• 18 nm — diameter of tobacco mosaic virus^[15] (Generally, viruses range in size from 20 nm to 450 nm.)
• 20 nm — width of bacterial flagellum^[16]
• 20 nm to 80 nm — thickness of cell wall in Gram-positive bacteria^[17]
• 22 nm — Smallest feature size of production microprocessors in September 2009^[18]
• 22 nm — the average half-pitch of a memory cell expected to be manufactured at around the 2011–2011 time frame.
• 30 nm — lower size of cooking oil smoke^[13]
• 32 nm — the average half-pitch of a memory cell manufactured at around the 2009–2010 time frame.
• 45 nm — the average half-pitch of a memory cell manufactured at around the 2007–2008 time frame.
• 50 nm — upper size for airborne virus particles^[13]
• 50 nm — flying height of the head of a hard disk^[19]
• 65 nm — the average half-pitch of a memory cell manufactured at around the 2005–2006 time frame.
• 90 nm — the average half-pitch of a memory cell manufactured at around the 2002–2003 time frame.
• 100 nm — larger than 90% of the particles of wood smoke (ranges from 7 to 3000 nanometres)^[13]

100 nanometres

Lengths between 10⁻⁷ and 10⁻⁶ m (100 nm and 1 µm).

• 100 nm — greatest particle size that can fit through a surgical mask^[20]
• 100 nm — 90% of particles in wood smoke are smaller than this.
• 120 nm — greatest particle size that can fit through a ULPA filter
• 120 nm — diameter of a human immunodeficiency virus (HIV) ^[21]
• 125 nm — standard depth of pits on compact discs (width: 500 nm, length: 850 nm to 3.5 µm)
• 180 nm — typical length of the rabies virus
• 200 nm — typical size of a Mycoplasma bacterium, among the smallest bacteria
• 300-400 nm — near ultraviolet wavelength
• 300 nm — greatest particle size that can fit through a HEPA (high efficiency particulate air) filter (N100 removes up to 99.97% at 0.3 micrometres, N95 removes up to 95% at 0.3 micrometres)
• 400–420 nm — wavelength of violet light
• 420–440 nm — wavelength of indigo light
• 440–500 nm — wavelength of blue light
• 500–520 nm — wavelength of cyan light
• 520–565 nm — wavelength of green light
• 565–590 nm — wavelength of yellow light
• 590–625 nm — wavelength of orange light
• 625–700 nm — wavelength of red light
• 700–1400 nm — wavelength of near-infrared radiation

1 micrometre

A clickable mosaic of objects
at scales within direct human experience, from the micrometric (10⁻⁶ m, top left) to the multi-kilometric (10⁵ m, bottom right).

To help compare different orders of magnitude this page lists some items with lengths between 10⁻⁶ and 10⁻⁵ m (between 1 and 10 micrometres, or µm).

• ~0.7–300 µm — Wavelength of infrared radiation
• 1 µm — the side of square of area 10⁻¹² m²
• 1 µm — edge of cube of volume 10⁻¹⁸ m³ (one femtolitre)
• 1–10 µm — diameter of a typical bacterium
• 1.55 µm — wavelength of light used in optical fibre
• 3–4 µm — size of a typical yeast cell
• 5 µm — length of a typical human spermatozoon's head^[22]
• 6 µm — anthrax spore
• 7 µm — diameter of the nucleus of a typical eukaryotic cell
• about 7 μm — diameter of human red blood cells^[23]
• 3–8 µm — width of strand of spider web silk^[24]
• 8 µm — width of a chloroplast
• 9 µm — thickness of the tape in a 120-minute compact cassette.
• about 10 µm — size of a fog, mist or cloud water droplet

10 micrometres

To help compare different orders of magnitude, this page lists lengths between 10⁻⁵ and 10⁻⁴ m (10 µm and 100 µm).

• 10 µm — width of cotton fibre^[25]
• 10 µm — transistor width of the Intel 4004, the world's first commercial microprocessor
• 10 µm — mean longest dimension of a human red blood cell
• 5–20 µm — dust mite excreta^[26]
• 10.6 µm — wavelength of light emitted by a carbon dioxide laser
• 15 µm — width of silk fibre
• 16 µm — diameter of a micromirror in a typical Digital micromirror device
• 17 µm — length of a tobacco mosaic virus
• 17 µm — minimum width of a strand of human hair^[27]
• 17.6 µm — one twip, a unit of length in typography
• 10 to 55 µm — width of wool fibre^[25]
• 25.4 µm — 1/1000 inch, commonly referred to as 1 mil in the U.S. and 1 thou in the UK
• 30–50 µm — diameter of a minicolumn in the human cortex
• 50 µm — typical length of Euglena gracilis, a flagellate protist
• 50 µm — typical length of a human liver cell, an average-sized body cell
• 78 µm — width of a pixel on the display of the iPhone 4, marketed as Retina Display^[28]
• 90 µm — paper thickness in average
• 1 myriometre, Distances shorter than 100 µm

100 micrometres

To help compare different orders of magnitude, this page lists lengths between 10⁻⁴ and 10⁻³ m (100 µm and 1 mm).

• 100 µm – 1/10 of a millimetre
• 100 µm – 0.00394 inches
• 100 µm – average diameter of a strand of human hair^[27]
• 100 µm – thickness of a coat of paint
• 100 µm – length of a dust particle
• 120 µm – diameter of a human ovum
• 170 µm – length of the largest sperm cell in nature^[29][30]
• 181 µm – maximum width of a strand of human hair^[27]
• 100–400 µm – length of Demodex mites living in human hair follicles
• 200 µm – typical length of Paramecium caudatum, a ciliate protist
• 250–300 µm – length of a dust mite^[31]
• 340 µm – length of a single pixel on a 17-inch monitor with a resolution of 1024×768
• 500 µm – typical length of Amoeba proteus, an amoeboid protist
• 500 µm – MEMS micro-engine
• 560 µm - thickness of the central area of a human cornea^[32]
• 760 µm – thickness of a credit card

1 millimetre

To help compare different orders of magnitude this page lists lengths between 10⁻³ and 10⁻² m (1 mm and 1 cm).

• 1.0 mm — 1/7003100000000000000♠1000 of a metre
• 1.0 mm — 6998393700000000000♠0.03937 inches or  ⁵⁄₁₂₇ (exactly)
• 1.0 mm — side of square of area 1 mm²
• 1.0 mm — diameter of a pinhead
• 1.5 mm — length of average flea
• 2.54 mm — distance between pins on old DIP (dual-inline-package) electronic components
• 5 mm — length of average red ant
• 5.56×45mm NATO — standard ammunition size
• 7.62×51mm NATO — common military ammunition size

1 centimetre

A clickable mosaic of objects
at scales within direct human experience, from the micrometric (10⁻⁶ m, top left) to the multi-kilometric (10⁵ m, bottom right).

Lengths between 10⁻² and 10⁻¹ m (1and 10 cm).

• 1 cm — 10 millimetres
• 1 cm — 0.39 inches
• 1 cm — edge of square of area 1 cm²
• 1 cm — edge of cube of volume 1 ml
• 1 cm — approximate width of average fingernail
• 1.5 cm — length of a very large mosquito
• 2 cm — approximate width of an adult human finger
• 2.54 cm — 1 inch
• 3.1 cm — 1 attoparsec (10⁻¹⁸ parsecs)
• 3.5 cm — width of film commonly used in motion pictures and still photography
• 4.3 cm — minimum diameter of a golf ball^[33]
• 7.3-7.5 cm — diameter of a baseball^[34]
• 8.6 cm × 5.4 cm — dimensions of a typical credit card^[35]

1 decimetre

Lengths between 10 and 100 centimetres (10⁻¹ and 1 metre).

Conversions

10 centimetres (abbreviated to 10 cm) is equal to

• 1 decimetre (dm), a term not in common use
• 100 millimetres
• 3.9 inches
• A side of a square of area 0.01 m₂ ^{[note 1]}
• The edge of a cube with a volume of 6997100000000000000♠1×10⁻³ m^{3[note 1]} (one litre)

Wavelengths

• 10 cm = 1.0 dm^{[note 1]} – wavelength of the highest UHF radio frequency, 3 GHz
• 12 cm = 1.2 dm – wavelength of the 2.45 GHz ISM radio band
• 21 cm = 2.1 dm – wavelength of the 1.4 GHz hydrogen emission line, a hyperfine transition of the hydrogen atom
• 100 cm = 10 dm – wavelength of the lowest UHF radio frequency, 300 MHz

Human-defined scales and structures

• 10.16 cm = 1.016 dm — 1 hand used in measuring height of horses (4 inches)
• 12 cm = 1.2 dm — diameter of a Compact Disc (CD) (= 120 mm)
• 15 cm = 1.5 dm — length of a Bic pen with cap on
• 22 cm = 2.2 dm — diameter of a typical soccer ball
• 30.48 cm = 3.048 dm — 1 foot
• 30 cm = 3 dm — typical school-use ruler length (= 300 mm)
• 60 cm = 6 dm — standard depth (front to back) of a domestic kitchen worktop in Europe (= 600 mm)
• 90 cm = 9 dm — average length of a rapier, a fencing sword^[36]
• 91.44 cm = 9.144 dm — one yard
• Cigarettes 100 mm (4 in) in length

Nature

• 10 cm = 1 dm — diameter of the human cervix upon entering the second stage of labour
• 14 cm = 1.4 dm — length of average human penis
• 15 cm = 1.5 dm — approximate size of largest beetle species
• 29 cm = 2.9 dm — length of average human foot
• 29.98 cm = distance light travels in one nanosecond
• 31 cm = 3.1 dm — wingspan of largest butterfly species Ornithoptera alexandrae
• 50 to 65 cm — a pizote's tail
• 66 cm — length of the longest pine cones (produced by the sugar pine^[37])

Longer

1. 1 metre
2. 1 decametre
3. 1 hectometre
4. 1 kilometre
5. 1 myriametre
6. 100 kilometres
7. 1 megametre
8. 10 megametres
9. 100 megametres

1 gigametre

Click on the thumbnail image to jump to the desired order of length magnitude: top-left is 1e6m, lower-right is 1e17m. (Image description)

Upper part: Gamma Orionis, Algol B, the Sun (centre), underneath their darker mirror images (artist's interpretation), and other objects, to scale.

Lengths starting at 10⁹ metres (1 gigametre (Gm) or 1 million kilometres).

Distances shorter than 10⁹ metres

• 1.4 Gm — Diameter of Sun^[38]
• 1.5 Gm — (proposed) Expected orbit from Earth of the James Webb Space Telescope
• 2.19 Gm — Closest approach of Comet Lexell to Earth, happened on 1 July 1770; closest comet approach on record
• 3 Gm — Total length of "wiring" in the human brain.^[39]
• 4.2 Gm — Diameter of Algol B
• 5.0 Gm — Closest approach of Comet Halley to Earth, happened on 10 April 837
• 5.0 Gm — (proposed) Size of the arms of the giant triangle shaped Michelson interferometer of the Laser Interferometer Space Antenna (LISA) planned to start observations in or around 2015.
• 7.9 Gm — Diameter of Gamma Orionis
• 9.0 Gm — Estimated diameter of the event horizon of Sagittarius A*, the supermassive black hole in the center of the Milky Way galaxy

Longer

1. 10 gigametres
2. 100 gigametres
3. 1 terametre
4. 10 terametres
5. 100 terametres
6. 1 petametre
7. 10 petametres
8. 100 petametres
9. 1 exametre
10. 10 exametres
11. 100 exametres
12. 1 zettametre
13. 10 zettametres
14. 100 zettametres
15. 1 yottametre
16. 10 yottametres
17. 100 yottametres

See also

• Length
• Orders of magnitude (length)

Notes

References