The following are examples of orders of magnitude for different lengths.
Overview Scale Range (m) Unit Example items ≥ <Subatomic– 0– Gravitational singularity 10−36 10−33 Fixed value (not a range). Quantum foam, string 10−18 10−15 am Proton, neutron, pion Atomic to cellular 10−15 10−12 fm Atomic nucleus 10−12 10−9 pm Wavelength of gamma rays and X-rays, hydrogen atom 10−9 10−6 nm DNA helix, virus, wavelength of optical spectrum, transistors used in CPUs Cellular to human 10−6 10−3 μm Bacterium, fog water droplet, human hair's diameterThe diametre of human hair ranges from 17 to 181 μm 10−3 1 mm Mosquito, golf ball, domestic cat, violin, football Human to astronomical 1 103 m Piano, human, automobile, african bush elephant, sperm whale, football field, Eiffel Tower 103 106 km Mount Everest, length of Panama Canal and Trans-Siberian Railway, larger asteroid Astronomical 106 109 Mm The Moon, Earth, one light-second 109 1012 Gm Sun, one light-minute, Earth's orbit 1012 1015 Tm Orbits of outer planets, Solar System 1015 1018 Pm A light-year, the distance to Proxima Centauri 1018 1021 Em Galactic arm 1021 1024 Zm Milky Way, distance to Andromeda Galaxy 1024 1027 Ym Huge-LQG, Hercules–Corona Borealis Great Wall, Observable universe
Detailed list To help compare different orders of magnitude, the following list describes various lengths between metres and metres. Metres are used in these tables to provide a common reference point, but metric prefixes above "k" are not commonly used with metres. So for example, 1.21 Gm would more commonly be written as 1.21 million km or (in scientific notation) 1.21 × 106 km. Interplanetary distances are also commonly measured in astronomical units. Distances on the interstellar or larger scale are typically measured in light-years or parsecs.
Subatomic scale Factor (m) Multiple Value Item 0 0 0 Singularity10−35 1 Planck length 0.0000162 qm Planck length; typical scale of hypothetical loop quantum gravity or size of a hypothetical string and of branes; according to string theory, lengths smaller than this do not make any physical sense. Quantum foam is thought to exist at this scale. 10−24 1 yoctometre (ym) 142 ym Effective cross section radius of 1 MeV neutrinos (6.3 × 10−44 cm2, which gives an effective radius of about 1.42 × 10−22 m) 10−21 1 zeptometre (zm) Preons, hypothetical particles proposed as subcomponents of quarks and leptons; the upper bound for the width of a cosmic string in string theory 7 zm Effective cross section radius of high-energy neutrinos (area for 20 GeV about 10 × 10−42 m2 gives effective radius of about 2 × 10−21 m; for 250 GeV about 150 × 10−42 m2 gives effective radius of about 7 × 10−21 m) 310 zm De Broglie wavelength of protons at the Large Hadron Collider (4 TeV ) 10−18 1 attometre (am) Upper limit for the size of quarks and electrons Sensitivity of the LIGO detector for gravitational waves Upper bound of the typical size range for "fundamental strings" 10−17 10 am Range of the weak force 10−16 100 am 850 am Approximate charge radius of the proton
Atomic to cellular scale
Factor (m)MultipleValueItem 10−15 1 femtometre (fm, fermi)1 fmApproximate limit of the gluon-mediated color force between quarks1.5 fmEffective cross section radius of an 11 MeV proton(diametre of the scattering cross section of an 11 MeV proton with a target proton)2.81794 fmClassical electron radius3 fmApproximate limit of the meson-mediated nuclear binding force750 to 822.25 fmLongest wavelength of gamma rays10−121 picometre (pm)1.75 to 15 fmDiameter range of the atomic nucleus1 pmDistance between atomic nuclei in a white dwarf2.4 pmCompton wavelength of electron5 pmWavelength of shortest X-rays10−1110 pm28 pmRadius of helium atom53 pmBohr radius (radius of a hydrogen atom) 10−10 100 pm100 pm1 ångström (also covalent radius of sulfur atom)154 pmLength of a typical covalent bond (C–C)280 pmAverage size of the water molecule (actual lengths may vary)500 pmWidth of protein α helix 10−9 1 nanometre (nm)1 nmDiameter of a carbon nanotube diameter of smallest transistor gate (as of 2016)2 nmDiameter of the DNA helix2.5 nmSmallest microprocessor transistor gate oxide thickness ()3.4 nmLength of a DNA turn (10 bp)6–10 nmThickness of cell membrane 10−8 10 nm10 nmUpper range of thickness of cell wall in Gram-negative bacteria10 nm, 10 nanometres was the smallest semiconductor device fabrication node40 nmExtreme ultraviolet wavelength50 nmFlying height of the head of a hard disk 10−7 100 nm121.6 nmWavelength of the Lyman-alpha lineCohn, J. University of California, Berkeley Lyman alpha systems and cosmology . Retrieved 21 February 2009.120 nmTypical diameter of the human immunodeficiency virus (HIV)400–700 nmApproximate wavelength range of visible light
Cellular to human scale
Factor (m)MultipleValueItem 10−6 1 micrometre (μm) (also called 1 micron)1–4 μmTypical length of a bacterium4 μmTypical diameter of spider silk7 μmTypical size of a red blood cell 10−5 10 μm10 μmTypical size of a fog, mist, or cloud water droplet10 μmWidth of transistors in the Intel 4004, the world's first commercial microprocessor12 μmWidth of acrylic fiber17–181 μmWidth range of human hairAccording to The Physics Factbook, the diametre of human hair ranges from 17 to 181 μm 10−4 100 μm340 μmSize of a pixel on a 17-inch monitor with a resolution of 1024×768560 μmThickness of the central area of a human cornea or, diameter of a grain of salt.750 μmMaximum diameter of Thiomargarita namibiensis, the second largest bacterium ever discovered 10−3 1 millimetre (mm)~5 mmLength of an average flea is 1–10 mm (usually <5 mm)Order Siphonaptera – Fleas – BugGuide.Net Accessed 29 April 20142.54 mmOne-tenth inch; distance between pins in DIP (dual-inline-package) electronic components5.70 mmApproximate diameter of the projectile in 5.56×45 mm NATO ammunition 10−2 1 centimetre (cm)20 mmApproximate width of an adult human finger54 mm × 86 mmDimensions of a credit card, according to the ISO/IEC 7810 ID-1 standard73–75 mmDiameter of a baseball, according to Major League Baseball guidelines 10−1 1 decimetre (dm)120 mmDiameter of a compact disc660 mmLength of the longest pine cones, produced by the sugar pine900 mmAverage length of a rapier, a fencing sword
Human to astronomical scale
Factor (m)MultipleValueItem 1 (100) 1 metre (m)1 m (exactly)Since 2019, defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second, where the second is defined by a hyperfine transition frequency of caesium.2.72 mHeight of Robert Wadlow, tallest-known human.8.38 mLength of a London bus (AEC Routemaster) 101 1 decametre (dam)33 mLength of the longest known blue whale52 mHeight of the Niagara Falls93.47 mHeight of the Statue of Liberty 102 1 hectometre (hm)105 mLength of a typical football field137 m (147 m)Height (present and original) of the Great Pyramid of Giza300 mHeight of the Eiffel Tower, one of the famous monuments of Paris979 mHeight of the Salto Angel in Venezuela, the world's highest free-falling waterfall 103 1 kilometre (km)2.3 kmLength of the Three Gorges Dam, the largest dam in the world3.1 kmNarrowest width of the Strait of Messina, separating Italy and Sicily8.848 kmHeight of Mount Everest, the highest mountain on Earth 104 10 km (1 Myriametre)10.9 kmDepth of the Challenger Deep in the Mariana Trench, the deepest-known point on Earth's surface27 kmCircumference of the Large Hadron Collider, (and still as of November 2025) the largest and highest energy particle accelerator42.195 kmLength of a marathon105100 km100 kmThe distance the IAU considers to be the limit to space, called the Karman line163 kmLength of the Suez Canal, connecting the Mediterranean Sea to the Red Sea491 kmLength of the Pyrenees, the mountain range separating Spain and France600 kmThermosphere height 974.6 kmGreatest diameter of the dwarf planet Ceres. 106 1 megametre (Mm)2.38 MmDiameter of dwarf planet Pluto, formerly the smallest planet categoryThe exact category (asteroid, dwarf planet, or planet) to which particular Solar System objects belong, has been subject to some revision since the discovery of extrasolar planets and trans-Neptunian objects in the Solar System3.48 MmDiameter of the Moon5.2 MmTypical distance covered by the winner of the 24 Hours of Le Mans automobile endurance race6.259 MmLength of the Great Wall of China6.371 MmAverage radius of Earth6.378 MmEquatorial radius of Earth6.6 MmApproximate length of the two longest rivers, the Nile and the Amazon7.821 MmLength of the Trans-Canada Highway9.288 MmLength of the Trans-Siberian Railway, longest in the world
Astronomical scale