How many millimetre in 1 light-year?
The answer is 9.4607304725808E+18.
We assume you are converting between millimetre and light year.
You can view more details on each measurement unit: millimetre or
light-year
The SI base unit for length is the metre.
1 metre is equal to 1000 millimetre, or 1.0570008340246E-16 light-year.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between millimetres and light years.
Type in your own numbers in the form to convert the units!

››Want other units?

You can do the reverse unit conversion from
light-year to millimetre, or enter any two units below:

A millimetre (American spelling: millimeter, symbol mm) is one thousandth of a metre, which is the International System of Units (SI) base unit of length. The millimetre is part of a metric system. A corresponding unit of area is the square millimetre and a corresponding unit of volume is the cubic millimetre.

››Definition: Light-year

A light year, abbreviated ly, is the distance light travels in one year: roughly 9.46 × 1012 kilometres (9.46 petametres, or about 5.88 × 1012 (nearly six trillion) miles). More specifically, a light year is defined as the distance that a photon would travel, in free space and infinitely far away from any gravitational or magnetic fields, in one Julian year (365.25 days of 86400 seconds each).

››Metric conversions and more

ConvertUnits.com provides an online
conversion calculator for all types of measurement units.
You can find metric conversion tables for SI units, as well
as English units, currency, and other data. Type in unit
symbols, abbreviations, or full names for units of length,
area, mass, pressure, and other types. Examples include mm,
inch, 100 kg, US fluid ounce, 6'3", 10 stone 4, cubic cm,
metres squared, grams, moles, feet per second, and many more!