Convert Light Year to Millimeter
Use this free converter to change light years (ly) into millimeters (mm). Light year and millimeter both measure length. As a quick reference, 1 ly equals 9.4607e+18 mm, and 1 mm equals 1.0570e-19 ly.
Free · runs in your browser · no sign-up
Millimeter (mm)
9.4607e+18
1 ly = 9.4607e+18 mm
Length conversion table
| Light Year | Millimeter |
|---|---|
| 0.01 | 9.4607e+16 |
| 0.1 | 9.4607e+17 |
| 0.5 | 4.7304e+18 |
| 1 | 9.4607e+18 |
| 2 | 1.8921e+19 |
| 3 | 2.8382e+19 |
| 5 | 4.7304e+19 |
| 10 | 9.4607e+19 |
| 20 | 1.8921e+20 |
| 25 | 2.3652e+20 |
| 50 | 4.7303e+20 |
| 100 | 9.4607e+20 |
| 1,000 | 9.4607e+21 |
How to convert Light Year to Millimeter
Multiply the light year value by 9.4607e+18 to get millimeters.
- Enter the number of light years you want to convert.
- The converter instantly shows the equivalent value in millimeters.
- Worked example: 15 ly × 9.4607e+18 = 1.4191e+20 mm.
- Use the swap button to reverse the conversion (millimeter to light year).
About these units
Light Year (ly)
- Definition
- A light-year (ly) is the distance light travels in one year in a vacuum, about 9.46 trillion kilometers.
- History
- The concept arose in the 19th century as astronomers sought an intuitive way to express the vast distances between stars.
- Current use
- Light-years express distances to stars and galaxies in astronomy and popular science.
Millimeter (mm)
- Definition
- A millimeter (mm) is one thousandth of a meter, used where small, precise measurements are needed.
- History
- Like other metric subdivisions it was defined in the 1790s using the prefix "milli-" (one thousandth).
- Current use
- Engineers, machinists, and manufacturers specify tolerances in millimeters, and rainfall is commonly reported in mm.
Frequently asked questions
How many millimeters are in a light year?
There are 9.4607e+18 mm in 1 ly. To convert, multiply the number of light years by 9.4607e+18.
How do I convert light years to millimeters?
Multiply the light year value by 9.4607e+18 to get millimeters. For example, 10 ly = 9.4607e+19 mm.
Is this light year-to-millimeter converter free?
Yes. This converter is completely free, runs entirely in your browser, and requires no sign-up. Your inputs never leave your device.
Convert Light Year to other length units
| Unit | 1 Light Year equals |
|---|---|
| Meter (m) | 9.4607e+15 m |
| Kilometer (km) | 9.4607e+12 km |
| Centimeter (cm) | 9.4607e+17 cm |
| Millimeter (mm) | 9.4607e+18 mm |
| Micrometer (µm) | 9.4607e+21 µm |
| Nanometer (nm) | 9.4607e+24 nm |
| Mile (mi) | 5.8786e+12 mi |
| Yard (yd) | 1.0346e+16 yd |
| Foot (ft) | 3.1039e+16 ft |
| Inch (in) | 3.7247e+17 in |
| Nautical Mile (nmi) | 5.1084e+12 nmi |