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Astronomical Unit Calculator

Use this astronomical unit calculator to translate solar-system distances into everyday distance units without losing the AU reference.

Live converter

Astronomical units

Converted distance149,597,870.7

1 astronomical units to kilometers.

Astronomical units1 AU

149,597,870.7 kilometers.

Miles92,955,807.3 mi

149,597,870,700 meters.

AU reference
ReferenceValue
1 AU149,597,870,700 m
1 AU149,597,870.7 km
1 AUAbout 92,955,807.3 mi

Formula

Astronomical unit formula

1 AU = 149,597,870,700 meters exactly

The calculator uses the IAU fixed astronomical unit and then applies standard length conversions.

How to use

Steps

  1. Enter the distance value.
  2. Choose whether the input is in AU, kilometers, meters, or miles.
  3. Choose the target distance unit.
  4. Use the reference outputs to compare the same distance across common astronomy units.

Example

Sample calculation

Input1 AU
Kilometers149,597,870.7 km
MilesAbout 92,955,807.3 mi

Calculator use

Best for

  • Quick everyday math with the result and formula in one place.
  • Shopping, date, time, unit, school, or household comparisons.

Before relying on it

Check first

  • The calculator uses the IAU fixed astronomical unit and then applies standard length conversions.
  • Mixing units, dates, or original values across the same calculation.
  • Rounding early and then using the rounded number in another step.

Details

What to know before using the result

AU basis149,597,870,700 m

The astronomical unit is a fixed conventional length used for solar-system distances.

Best useLarge distance comparison

AU keeps planetary-scale distances readable while kilometers and miles help with familiar comparisons.

PrecisionRound for communication

Keep only the significant figures your source distance supports.

Source notes

References used for this calculator

International Astronomical UnionDefines the astronomical unit as exactly 149,597,870,700 meters.NIST SI GuideLists standard length conversion factors used for meter, kilometer, mile, and related units.

Benchmarks

How to read the result

1 AU: 149,597,870.7 km.

Solar-system distance reference.

0.5 AU: 74,798,935.35 km.

Useful fractional-AU check.

1 AU: About 92.96 million miles.

Common U.S. customary comparison.

Calculator accuracy

Methodology and assumptions

Formula, inputs, limitations and review record
Formula

1 AU = 149,597,870,700 meters exactly

Inputs used

Distance, From unit, To unit

Limitations

Everyday results are quick planning checks. Unit choices, rounding, labels, measurements, local prices, and real-world constraints can change the final decision.

Review record

Catalog QA baseline on June 6, 2026. This date marks the catalog-wide automated and editorial QA baseline, not a tool-specific expert review.

Cite this page

Toolkit Shelf. Astronomical Unit Calculator. https://toolkitshelf.com/tools/astronomical-unit-calculator

FAQ

Common questions

What is one astronomical unit?

One astronomical unit is exactly 149,597,870,700 meters by IAU definition.

Is an AU the exact Earth-Sun distance?

No. It is a fixed reference length. Earth's actual distance from the Sun varies through its orbit.

When should I use AU instead of kilometers?

Use AU when solar-system distances become too large to scan comfortably in kilometers or miles.