Convert Light Year to Yard
Convert light years to yards instantly. 1 light year = 1.034638e+16 yard — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Yard to Light Year converter for the reverse conversion.
Units explained
Light Year
A light year is the distance light travels in one Julian year in vacuum — exactly 9,460,730,472,580,800 meters (about 9.46×10¹⁵ m). It is the most common unit for expressing inter-stellar distances in non-technical astronomy.
Defined as the speed of light (299,792,458 m/s, exact) multiplied by one Julian year (365.25 days × 86400 seconds/day). Both factors are exact, making the light year exact by definition.
Light years are used in popular astronomy, science journalism, and stellar distance descriptions. The nearest star (Proxima Centauri) is 4.24 ly away; the Milky Way is about 100,000 ly across.
Concept of distance-as-time used since the 19th century; the modern exact definition follows from the 1983 SI definition of the meter via the speed of light.
Yard
A yard is an Imperial and US customary unit of length equal to 3 feet or exactly 0.9144 meters. It is used for medium distances, particularly in athletics and fabric/textile measurement.
The yard's origin is contested but traditionally attributed to the length from the tip of King Henry I's nose to the end of his outstretched thumb. It was standardized in English law from the medieval period and definitively fixed at 0.9144 m exactly by the 1959 International Yard and Pound Agreement.
Yards are used in American football (10 yards for a first down), golf course distances, fabric and carpet sales in the US, and short-distance running events. The UK uses yards informally and on road signs for short distances.
Standardized in English law from the Middle Ages; fixed at 0.9144 m exactly by the 1959 International Yard and Pound Agreement.
Light Year to Yard conversion formula
The relationship between light years and yards:
To convert light years to yards, multiply the value in light years by 1.034638e+16. To reverse, multiply yards by 9.665216e-17.
How to use this converter
Type a value into the calculator. The result in yards updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Yard to Light Year converter for the reverse direction.
Step-by-step: convert light years to yards
- Write down the value in light years (ly).
- Multiply that value by the factor 1.034638e+16.
- The product is the equivalent value in yards (yd).
- To reverse, multiply the yard value by 9.665216e-17.
Worked examples
Example 1 — Convert 1 ly to yd:
1 × 1.034638e+16 = 1.034638e+16 yd
Example 2 — Convert 100 ly to yd:
100 × 1.034638e+16 = 1.034638e+18 yd
Light Year to Yard conversion table
Standard reference values for converting light years to yards:
| Light Year [ly] | Yard [yd] |
|---|---|
| 0.01 | 1.034638e+14 |
| 0.1 | 1.034638e+15 |
| 1 | 1.034638e+16 |
| 2 | 2.069276e+16 |
| 3 | 3.103914e+16 |
| 4 | 4.138552e+16 |
| 5 | 5.17319e+16 |
| 10 | 1.034638e+17 |
| 20 | 2.069276e+17 |
| 30 | 3.103914e+17 |
| 40 | 4.138552e+17 |
| 50 | 5.17319e+17 |
| 100 | 1.034638e+18 |
| 500 | 5.17319e+18 |
| 1000 | 1.034638e+19 |
Frequently asked questions
How many yards is 1 light year?
How do I convert light years to yards?
How do I convert yards back to light years?
How many yards is 100 light years?
Popular length unit conversions
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Metric / SI (4 units)
Imperial / US Customary (4 units)
Astronomical (8 units)
Sources & references
Conversion factor (1 ly = 1.034638e+16 yd) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.