This distance converter uses the exact IAU astronomical-unit definition and captured reference constants for solar-system scale conversions.
Conversion
Astronomical Unit Calculator
Convert distances between the astronomical unit and common astronomy and metric scales.
Calculator
About this calculator
Formula notes
1 au = 149,597,870,700 m exactly; light years, parsecs, and solar radii use the captured reference constants.
Worked examples
- Example: 1 au equals 149,597,870.7 km, about 1.5813e-5 light-years, and about 215.03 solar radii.
- 1 light-year is about 63,241.1 astronomical units using the captured light-year constant.
How to use it
- Enter a nonnegative distance.
- Choose its unit from metres to light-years.
- Read astronomical units, kilometres, light years, parsecs, and solar radii.
Frequently asked questions
Which astronomical-unit definition is used?
The exact IAU 2012 definition: 1 au = 149,597,870,700 metres.
Are these values current orbital positions?
No. The tool converts fixed distance units; actual solar-system distances change with orbits and time.
Limits and interpretation
- The converter uses fixed IAU and captured constants; real solar-system distances vary with orbital motion and time.
- Light years, parsecs, and solar radii are reference-scale conversions, not precision astrometry.