How many feet are in a light year?

One light year equals approximately 3.1039 × 10¹⁶ feet (about 31 quadrillion feet). Equivalently, 1 foot is roughly 3.221 × 10⁻¹⁷ light years.

What is a light year?

A light year (ly) is the distance light travels in one Julian year (365.25 days) in a vacuum at exactly 299,792,458 meters per second. It equals approximately 9.461 × 10¹⁵ meters or about 5.879 trillion miles.

Why is the light-year value so small for most foot inputs?

A light year is an enormous distance — roughly 63,241 times the Earth-Sun distance. Even a mile is only about 1.7 × 10⁻¹³ light years, so foot-scale distances produce extremely small light-year values that require scientific notation to read clearly.

How do I read scientific notation results?

Scientific notation writes a number as a coefficient times a power of 10. For example, 3.22 × 10⁻¹⁷ means 0.0000000000000000322. The negative exponent tells you how many places to move the decimal point to the left.

What is an astronomical unit (AU)?

An astronomical unit is the average distance from the Earth to the Sun — about 92.96 million miles or 1.496 × 10⁸ km. One light year equals approximately 63,241 AU.

How does this differ from miles to light years?

One mile equals 5,280 feet, so a mile-to-light-year result is exactly 5,280 times larger than the foot-to-light-year result for the same numeric input. You can easily cross-check by entering 5280 feet here.

Feet to Light Years Converter

Enter a distance in feet and instantly see the equivalent in light years, astronomical units, parsecs, and kilometers.

Enter Distance in Feet

Feet (ft)

Quick examples

Converted Values

Light Years (scientific)

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Light Years (decimal) —

Astronomical Units (AU) —

Parsecs (pc) —

Kilometers (km) —

Astronomical Distance Reference

Click any row to load that value into the converter above.

Object / Distance	Feet (ft)	Light Years
1 foot	1 ft	3.222 × 10⁻¹⁷ ly
1 yard (3 ft)	3 ft	9.665 × 10⁻¹⁷ ly
1 mile (5,280 ft)	5,280 ft	1.701 × 10⁻¹³ ly
Height of Everest	≈ 29,032 ft	9.353 × 10⁻¹³ ly
Earth radius	≈ 2.09 × 10⁷ ft	6.734 × 10⁻¹⁰ ly
Earth–Moon distance	≈ 1.26 × 10⁹ ft	4.059 × 10⁻⁸ ly
1 Astronomical Unit (AU)	≈ 4.91 × 10¹¹ ft	1.581 × 10⁻⁵ ly
Earth–Sun distance	≈ 4.91 × 10¹¹ ft	1.581 × 10⁻⁵ ly
1 Light Year	≈ 3.10 × 10¹⁶ ft	1.000 × 10⁰ ly
Distance to Proxima Centauri	≈ 1.32 × 10¹⁷ ft	4.240 × 10⁰ ly
Milky Way diameter	≈ 3.10 × 10²¹ ft	1.000 × 10⁵ ly

Summary

Enter a distance in feet and instantly see the equivalent in light years, astronomical units, parsecs, and kilometers.

How it works

Enter a distance value in feet in the input field.
The converter multiplies feet by 30.48 to get centimeters, then divides by 9.4607304725808 × 10¹⁷ to get light years.
The primary result is displayed in scientific notation (e.g. 1.017 × 10⁻¹⁵ ly) for clarity.
Related astronomical units — astronomical units (AU), parsecs, and kilometers — are shown below.
Results update instantly as you type.
Click a quick example or reference table row to load a preset value.

Use cases

Convert a human-scale distance (room size, running track, building height) to light years.
Understand how minuscule everyday distances are on a cosmic scale.
Verify astronomical unit conversions for physics or astronomy coursework.
Compare distances — from a football field to the orbit of Pluto — on a unified astronomical scale.
Use scientific notation output for academic papers or presentations.
Teaching aid for demonstrating the vastness of interstellar space.
Convert spacecraft trajectory distances expressed in feet to light-year equivalents.
Cross-check published astronomical figures in imperial vs. metric vs. astronomical units.

Frequently Asked Questions

Last updated: 2026-09-14 · Reviewed by Nham Vu