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Convert km to au

1 kilometer equals 6.6845871e-9 astronomical units. Enter a value below to convert instantly.

1 km
6.6845871e-9 AU

Multiply the number of kilometers by 6.684587122268446e-9 to get astronomical units. How this is calculated

Copy link puts your number after the #, which browsers never send to a server — but the link itself carries it, so anyone you send it to sees the value. Save keeps the unit pair in this browser only; clear it any time from your saved list.

Need the other direction? Convert astronomical unit to kilometer →

Formula

Multiply the number of kilometers by 6.684587122268446e-9 to get astronomical units.

Step by step

  1. Start with 1 km.
  2. Multiply by the conversion factor 6.684587122268446e-9.
  3. 1 × 6.684587122268446e-9 = 6.6845871e-9 AU.

Kilometers to Astronomical Units conversion table

Kilometers (km) Astronomical Units (AU)
1 6.6845871e-9
2 1.3369174e-8
3 2.0053761e-8
5 3.3422936e-8
10 6.6845871e-8
20 1.3369174e-7
50 3.3422936e-7
100 6.6845871e-7
500 0.0000033422936
1,000 0.0000066845871

Convert Kilometer to other length units

1 km expressed in every other length unit on this site.

  • Meter m 1,000
  • Hectometer hm 10
  • Dekameter dam 100
  • Decimeter dm 10,000
  • Centimeter cm 100,000
  • Millimeter mm 1,000,000
  • Micrometer µm 1,000,000,000
  • Nanometer nm 1,000,000,000,000
  • Picometer pm 1e+15
  • Femtometer fm 1e+18
  • Attometer am 1e+21
  • Megameter Mm 0.001
  • Gigameter Gm 0.000001
  • Terameter Tm 1e-9
  • Petameter Pm 1e-12
  • Exameter Em 1e-15
  • Angstrom Å 10,000,000,000,000
  • Mile mi 0.62137119
  • Yard yd 1,093.6133
  • Foot ft 3,280.8399
  • Inch in 39,370.079
  • Kiloyard kyd 1.0936133
  • League lea 0.20712373
  • Furlong fur 4.9709695
  • Chain ch 49.709695
  • Rod rd 198.83878
  • Perch perch 198.83878
  • Pole pole 198.83878
  • Rope rope 164.04199
  • Fathom fath 546.80665
  • Link li 4,970.9695
  • Hand hand 9,842.5197
  • Ell ell 874.89064
  • Barleycorn barleycorn 118,110.24
  • Mil mil 39,370,079
  • Microinch µin 39,370,079,000
  • Caliber cl 3,937,007.9
  • Centiinch cin 3,937,007.9
  • Nautical Mile nmi 0.5399568
  • Nautical Mile (UK) NM (UK) 0.53961182
  • Nautical League nl 0.1799856
  • Nautical League (UK) nl (UK) 0.17987061
  • Mile (US survey) mi (US) 0.62136995
  • Furlong (US survey) fur (US) 4.9709596
  • Chain (US survey) ch (US) 49.709596
  • Rod (US survey) rd (US) 198.83838
  • Fathom (US survey) fath (US) 546.80556
  • Foot (US survey) ft (US) 3,280.8333
  • Link (US survey) li (US) 4,970.9596
  • Inch (US survey) in (US) 39,370
  • League (statute) st.league 0.20712332
  • Pica pica 236,220.47
  • Point pt 2,834,645.7
  • Twip twip 56,692,913
  • Light Year ly 1.0570008e-13
  • Astronomical Unit AU 6.6845871e-9
  • Parsec pc 3.2407793e-14
  • Kiloparsec kpc 3.2407793e-17
  • Megaparsec Mpc 3.2407793e-20
  • Earth's Equatorial Radius R⊕(eq) 0.00015678559
  • Earth's Polar Radius R⊕(pol) 0.00015731304
  • Earth's Distance from Sun d⊕☉ 6.684492e-9
  • Sun's Radius R☉ 0.0000014374012
  • Bohr Radius a₀ 18,897,261,000,000
  • Electron Radius (classical) rₑ 3.5486912e+17
  • Fermi F 1e+18
  • X-unit X 9.9792432e+15
  • Planck Length ℓP 6.1871425e+37
  • Mile (Roman) mi (Rom) 0.67576517
  • Roman Actus actus 28.18591
  • Arpent arpent 17.087708
  • Cubit (UK) cubit 2,187.2266
  • Cubit (Greek) cubit (Gk) 2,160.8166
  • Long Cubit long cubit 1,874.7657
  • Reed reed 364.53777
  • Long Reed long reed 312.46094
  • Span (cloth) span 4,374.4532
  • Finger (cloth) finger 8,748.9064
  • Nail (cloth) nail 17,497.813
  • Handbreadth handbreadth 13,123.36
  • Fingerbreadth fingerbreadth 52,493.438
  • Aln aln 1,684.1317
  • Famn famn 561.37725
  • Ken ken 472.06329
  • Russian Archin archin 1,406.0742
  • Vara Castellana vara (cast) 1,197.3868
  • Vara Conuquera vara (con) 399.12894
  • Vara de Tarea vara (tarea) 399.12894
  • Ja (Korean foot) 자 3,300
  • Chi 치 33,000
  • Pun 푼 330,000
  • Gan 간 550
  • Jang 장 330
  • Ri (Korean) 리 2.5462963

About the kilometer

The kilometer (km) is a SI unit of length.

About the astronomical unit

The astronomical unit (AU) is a Other unit of length. Defined by the IAU as exactly 149,597,870,700 m — roughly the Earth–Sun distance.

Where this conversion is used

Converting kilometers to astronomical units comes up when measuring height, screen sizes, travel distances, fabric, and construction dimensions. Metric and Imperial length units are both in daily use, so quick conversion is often needed when following instructions from another country.

Related conversions

Frequently asked questions

How many astronomical units are in a kilometer?

One kilometer equals 6.6845871e-9 astronomical units.

How do you convert kilometers to astronomical units?

Multiply the number of kilometers by 6.684587122268446e-9 to get astronomical units.

What is 1 astronomical unit in kilometers?

One astronomical unit equals 149,597,870 kilometers.

When would I convert kilometers to astronomical units?

This conversion is common when measuring height, screen sizes, travel distances, fabric, and construction dimensions.

Conversion factors are based on internationally agreed unit definitions. See our methodology and sources for details on how these values are verified.