Astronomical units (au)
The astronomical unit (au) is a unit of length roughly equal to the average distance between the Earth and the Sun, about 149.6 million km or 93 million miles.
Convert astronomical units to any length unit
1 astronomical unit = 5,889,679,949,000 inches
Quick facts
- Unit
- Astronomical unit (plural: astronomical units)
- Symbol
- au
- Measures
- Length / Distance
- System
- Astronomical
- Equals
- 149,597,870,700 meters
- Definition
- Exactly 149,597,870,700 m, fixed by the IAU in 2012.
- Also written
- AU, UA
1 astronomical unit in other units
| Inches | 5,889,679,949,000 in |
| Meters | 149,597,870,700 m |
| Centimeters | 14,959,787,070,000 cm |
| Feet | 490,806,662,400 ft |
| Kilometers | 149,597,870.7 km |
| Miles | 92,955,807.27 mi |
| Millimeters | 149,597,870,700,000 mm |
| Yards | 163,602,220,800 yd |
What is an astronomical unit?
The astronomical unit (au) is a unit of length roughly equal to the average distance between the Earth and the Sun, about 149.6 million km or 93 million miles. It is the natural unit for distances within the solar system.
Where the astronomical unit sits among length units
The astronomical unit is number 221 of 231 on our scale of length units, ordered from smallest to largest.
What astronomical units are used for
- Distances between planets, asteroids and comets
- Orbits of exoplanets
Astronomical units in real life
- Mars orbits at about 1.52 au
- Neptune is about 30 au from the Sun
- Voyager 1 is more than 160 au from Earth
One astronomical unit is about the length of the distance to the Sun, or about 389 trips to the Moon laid end to end.
Top astronomical unit conversions
- Astronomical units to inches
- Astronomical units to meters
- Astronomical units to centimeters
- Astronomical units to feet
- Astronomical units to kilometers
- Astronomical units to miles
- Astronomical units to millimeters
- Astronomical units to yards
- Astronomical units to micrometers
- Astronomical units to nanometers
- Astronomical units to nautical miles
- Astronomical units to light-years
Common amounts of astronomical units
Convert astronomical units to all 230 other units
Metric (SI)
- au to m
- au to cm
- au to km
- au to mm
- au to µm
- au to nm
- au to dm
- au to pm
- au to fm
- au to dam
- au to hm
- au to Gm
- au to Mm
Imperial & US customary
- au to in
- au to ft
- au to mi
- au to yd
- au to ftm
- au to fur
- au to hh
- au to th
- au to ch
- au to lea
- au to rd
- au to cubit
- au to barleycorn
- au to li
- au to span
- au to line
- au to ell
- au to palm
- au to Ramsden's chain
- au to finger
- au to nail
- au to shaftment
US survey
Nautical
Astronomical
- au to ly
- au to pc
- au to kpc
- au to Mpc
- au to R⊕
- au to ls
- au to light-minute
- au to LD
- au to R☉
- au to Gpc
- au to light-day
- au to light-hour
- au to RJ
- au to light-week
- au to Hubble length
- au to siriometer
Scientific & atomic
Ancient
- au to Roman mile
- au to royal cubit
- au to stadion
- au to Biblical cubit
- au to Roman foot
- au to Greek foot
- au to Roman pace
- au to parasang
- au to Egyptian common cubit
- au to Egyptian digit
- au to Egyptian palm
- au to Gallic league
- au to Greek cubit
- au to Greek finger
- au to Roman cubit
- au to Roman digit
- au to Roman inch
- au to Roman palm
- au to Roman stadium
- au to Roman step
- au to handbreadth
- au to Biblical finger
- au to Biblical parasang
- au to Biblical span
- au to Greek palm
- au to Greek span
- au to Sabbath day's journey
- au to Talmudic mil
- au to bema
- au to beru
- au to day's journey
- au to diaulos
- au to dichas
- au to hippikon
- au to iteru
- au to khet
- au to kondylos
- au to kush
- au to nindan
- au to orgyia
- au to plethron
- au to pygme
- au to reed
- au to remen
- au to shu-si
- au to ush
East & Southeast Asian
- au to 里
- au to 尺
- au to 寸
- au to 尺
- au to 里
- au to 間
- au to 寸
- au to wa
- au to 리
- au to 丈
- au to 步
- au to 分
- au to 厘
- au to 分
- au to 치
- au to 町
- au to 자
- au to 丈
- au to khuep
- au to kujirajaku
- au to nio
- au to sen
- au to sok
- au to 引
- au to yot
- au to 厘
- au to 푼
- au to 毫
- au to 忽
- au to kraphiat
- au to 毛
- au to 丝
South Asian & Middle Eastern
- au to gaj
- au to kos
- au to yojana
- au to angul
- au to farsakh
- au to hasta
- au to arsin
- au to barid
- au to danda
- au to dhira
- au to qasaba
European (pre-metric)
- au to Swedish mil
- au to versta
- au to arshin
- au to lieue
- au to ligne
- au to pied du roi
- au to sazhen
- au to toise
- au to Irish mile
- au to Prussian mile
- au to Russian mile
- au to Scottish mile
- au to pouce
- au to vershok
- au to Danish mile
- au to French point
- au to Prussian ell
- au to Prussian foot
- au to Prussian inch
- au to Prussian rod
- au to Rhineland rod
- au to Russian foot
- au to Swiss hour
- au to aln
- au to aune
- au to duim
- au to dyuym
- au to famn
- au to liniya
- au to pyad
- au to Welsh mile
- au to fjardingsvag
- au to tochka
Spanish & Portuguese
- au to Castilian vara
- au to Spanish league
- au to Texas vara
- au to pulgada
- au to Castilian foot
- au to Mexican vara
- au to braca
- au to legua
- au to Portuguese foot
- au to Portuguese vara
- au to palmo
- au to polegada
- au to Spanish pace
- au to linea
- au to linha
- au to punto
Everyday comparisons
- au to American football field
- au to marathon
- au to smoot
- au to Earth circumference
- au to Eiffel Tower height
- au to Olympic pool length
- au to banana
- au to double-decker bus
- au to soccer pitch length
- au to Mount Everest height
- au to blue whale length
- au to credit card length
- au to human hair width
- au to Burj Khalifa height
- au to Earth diameter
- au to Empire State Building height
- au to Statue of Liberty height
- au to human height
- au to giraffe height
- au to grain of rice
- au to paperclip length
- au to pencil length
- au to sheppey
- au to smartphone length
Convert to astronomical units
- Inches to astronomical units
- Meters to astronomical units
- Centimeters to astronomical units
- Feet to astronomical units
- Kilometers to astronomical units
- Miles to astronomical units
- Millimeters to astronomical units
- Yards to astronomical units
- Micrometers to astronomical units
- Nanometers to astronomical units
- Nautical miles to astronomical units
- Light-years to astronomical units
Frequently asked questions
What is an astronomical unit?
The astronomical unit (au) is a unit of length roughly equal to the average distance between the Earth and the Sun, about 149.6 million km or 93 million miles.
How is the astronomical unit defined?
Exactly 149,597,870,700 m, fixed by the IAU in 2012.
How many inches are in an astronomical unit?
One astronomical unit equals 5,889,679,949,000 inches.
How many meters are in an astronomical unit?
One astronomical unit equals 149,597,870,700 meters.
How many centimeters are in an astronomical unit?
One astronomical unit equals 14,959,787,070,000 centimeters.