What is one astronomical unit in kilometers?

One astronomical unit is exactly 149,597,870.7 kilometers, as defined by the International Astronomical Union in 2012.

How do I convert astronomical units to light years?

Divide the AU value by 63,241. To find how many light years one AU equals, use the factor 1 AU = 0.0000158125 light years, or multiply AU by 63241 to get light years.

What is the difference between a light year and a parsec?

One light year is the distance light travels in a vacuum in one Julian year, about 9.46 trillion kilometers. One parsec is about 3.26 light years, or roughly 30.9 trillion kilometers, and is defined as the distance at which one astronomical unit subtends an angle of one arcsecond.

Can I convert astronomical units to miles?

Yes, one astronomical unit equals approximately 92,955,807 miles, using the IAU 2012 definition.

Which tool gives the most accurate astronomical unit conversion?

The Calculator Site states the exact IAU 2012 definition of 1 AU as 149,597,870.7 km (or 149,597,870,700 meters exactly), making it the most precise for that specific value.

Math & Numbers6 options compared

Astronomical Converter

Converts astronomical distance units using established scientific definitions. This calculator provides real-time conversion for the Astronomical Unit (AU) into various space-distance metrics, including kilometers, miles, light years, and parsecs. It utilizes the latest International Astronomical Union (IAU) standards to ensure accuracy when scaling measurements across vast cosmic distances,...

Editors’ Top PickBased on community votes

Starlight Tools

starlighttools.org

Space Unit Converter for AU, light-years, parsecs, kiloparsecs, megaparsecs, and kilometers with instant in-browser r...

Open Starlight Tools Read review →

Other OptionsRanked by votes

02
02
Omni Calculator
omnicalculator.com
Astronomical Unit Calculator that converts AU to meters, kilometers, miles, light years, and parsecs, with explanatio...
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03
03
Unitarium
unitarium.com
Length Units Converter that supports astronomical unit, light year, and parsec conversions alongside standard length ...
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04
04
MiniWebtool
miniwebtool.com
Length Converter that includes astronomical units like AU and light-years alongside metric and imperial units, provid...
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05
05
CodeBeautify
codebeautify.org
Astronomical Converter
Open site View details
06
06
The Calculator Site (thecalcs)
thecalcs.com
Astronomical Unit Calculator for converting AU to km, miles, light years, parsecs, and other space-distance units usi...
Open site View details

Side by side

Astronomical Converter options compared

Tool	Best for	Strengths	Limitations
Starlight Tools starlighttools.org	Quick multi-unit astronomy conversions	Instant in-browser results Shareable link updates Full results table with common distances	No explicit IAU version noted Fewer explanatory details
Omni Calculator omnicalculator.com	Conversions with educational explanations	Formulas and explanations provided Miles and imperial units included Community votes indicate reliability	Focus on AU conversion only Less concise for quick lookups
Unitarium unitarium.com	Basic astronomical length conversions	Supports AU, light-year, parsec alongside metric/imperial	Live page could not be fetched Limited community visibility
MiniWebtool miniwebtool.com	General length converter with astronomical units	Includes AU and light-years with metric/imperial units High monthly run volume indicates usage	No astronomical-specific features beyond unit support Generic interface
CodeBeautify codebeautify.org	Complex astronomical format conversions	Handles coordinate and time interval inputs Converts between multiple celestial unit systems	Primarily a format converter, not a distance calculator Low community votes suggest limited astronomy focus
The Calculator Site (thecalcs) thecalcs.com	Precise IAU-defined AU conversions	Exact IAU 2012 value: 149,597,870.7 km Real-time results with official definition stated Clear presentation of km and miles exact values	Calculator-only focus, no shareable link feature mentioned Fewer unit options than Starlight Tools

Buyer's guide

How to choose a astronomical converter

When picking an astronomical converter, first decide whether you need only distance conversions or also educational context. If you are doing quick lookups or need to share a specific conversion, choose a tool that updates the URL and provides a results table. If you need the officially exact IAU 2012 value of the astronomical unit in kilometers and miles, pick a site that states the precise meter value and definition year. Consider whether you prefer a dedicated astronomy tool or a general length converter that happens to include astronomical units.

Questions

Astronomical Converter FAQ

What is one astronomical unit in kilometers?: One astronomical unit is exactly 149,597,870.7 kilometers, as defined by the International Astronomical Union in 2012.
How do I convert astronomical units to light years?: Divide the AU value by 63,241. To find how many light years one AU equals, use the factor 1 AU = 0.0000158125 light years, or multiply AU by 63241 to get light years.
What is the difference between a light year and a parsec?: One light year is the distance light travels in a vacuum in one Julian year, about 9.46 trillion kilometers. One parsec is about 3.26 light years, or roughly 30.9 trillion kilometers, and is defined as the distance at which one astronomical unit subtends an angle of one arcsecond.
Can I convert astronomical units to miles?: Yes, one astronomical unit equals approximately 92,955,807 miles, using the IAU 2012 definition.
Which tool gives the most accurate astronomical unit conversion?: The Calculator Site states the exact IAU 2012 definition of 1 AU as 149,597,870.7 km (or 149,597,870,700 meters exactly), making it the most precise for that specific value.

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