Convert length and distance units — meters, feet, inches, kilometers, miles, light years and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 au | 1.496e+11 mm | |
| 0.01 au | 1.496e+12 mm | |
| 0.1 au | 1.496e+13 mm | |
| 1 au | 1.496e+14 mm | |
| 5 au | 7.48e+14 mm | |
| 10 au | 1.496e+15 mm | |
| 50 au | 7.480e+15 mm | |
| 100 au | 1.496e+16 mm | |
| 1000 au | 1.496e+17 mm |
Multiply the number of Astronomical Units by 1.496×1014 to get Millimeters. Formula: mm = au × 1.496×1014. Example: 10 au × 1.496×1014 = 1.496×1015 mm. To reverse, divide Millimeters by 1.496×1014 to get Astronomical Units.
| Astronomical Unit (au) | Millimeter (mm) |
|---|---|
| 0.001 au | 149600000000 mm |
| 0.01 au | 1.496×1012 mm |
| 0.1 au | 1.496×1013 mm |
| 0.5 au | 7.48×1013 mm |
| 1 au | 1.496×1014 mm |
| 2 au | 2.992×1014 mm |
| 5 au | 7.48×1014 mm |
| 10 au | 1.496×1015 mm |
| 20 au | 2.992×1015 mm |
| 50 au | 7.48×1015 mm |
| 100 au | 1.496×1016 mm |
| 250 au | 3.74×1016 mm |
| 500 au | 7.48×1016 mm |
| 1000 au | 1.496×1017 mm |
| 10000 au | 1.496×1018 mm |
To convert Astronomical Unit to Millimeter, multiply by 1.496×1014. Example: 10 au = 1.496×1015 mm
To convert Millimeter back to Astronomical Unit, divide by 1.496×1014 (multiply by 6.6845×10-15). Use the swap button above.
Start with 100 Astronomical Units = 1.496×1016 mm as your reference point. Scale up or down from there.
Historical measurements of the solar parallax used to determine the AU involved precise millimeter-scale observations of planetary transits. Converting the resulting AU value back to millimeters validates calibration.
Telescope and instrument designers express optical path lengths and detector dimensions in millimeters, while target distances are in AU — conversion needed when calculating angular resolution and diffraction limits.
Components manufactured for space telescopes and satellites are machined to millimeter tolerances, while the operational distances of these instruments (orbital radius, target separation) are expressed in AU.
Solar sail mission designers calculate radiation pressure in terms of AU from the Sun, then convert force and displacement into millimeters for sail membrane engineering specifications.
Detailed scale models of planetary orbits require converting AU distances to millimeters for the model scale — at 1mm = 1 million km scale, 1 AU = 149.6 mm, fitting the inner solar system on a desktop.
Modern geodetic reference frames define Earth's orbital motion in AU, with periodic corrections measured in millimeters applied to ground station coordinates using VLBI and laser ranging techniques.
The Astronomical Unit is a unit of Length measurement (symbol: au). 1 au = 1.496×1014 mm. Used in scientific and practical Length measurement applications.
The Millimeter is a unit of Length measurement (symbol: mm). It is part of an internationally recognised measurement system used alongside the Astronomical Unit.
The astronomical unit has ancient roots — Aristarchus of Samos attempted to measure the Earth-Sun distance around 270 BC, estimating it at 18–20 lunar distances (the true value is about 390). For centuries the AU was estimated using Venus transit observations and trigonometry. Edmond Halley organised the first coordinated international transit-of-Venus expedition in 1716. The modern value was determined by radar ranging to Venus in 1961. The IAU formally defined the AU as exactly 149,597,870,700 metres in 2012 — a fixed constant of physics, not a measured distance.
The millimetre was introduced alongside the metre in 1795 as part of the French metric system — one-thousandth of a metre, one-tenth of a centimetre. Its practical value emerged in precision engineering during the Industrial Revolution, when manufacturing tolerances first needed to be specified to sub-centimetre precision. By the 20th century, ISO engineering drawing standards adopted millimetres as the primary unit for all technical drawings worldwide. Today millimetres are the universal language of engineering — from watch mechanisms to aircraft fuselages.
Common use: Astronomical Unit to Millimeter conversion is needed when working with international standards, scientific publications, or reference materials that use different unit systems for Length measurement.