---
title: "Light-years to Feet — ly to ft converter"
description: "1 light-year = 3.1039142 × 10^16 feet. Convert light-years to feet with a full conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/light-years-to-feet/
site: "At One Place"
---

# Light-years to feet

**1 light-year in feet: 1 ly = 3.1039142 × 10^16 ft**

ft = ly × 3.103914197 × 10^16

To convert light-years to feet, multiply by 3.103914197 × 10^16. The table below gives the values people look up most often, and the converter works for any number.

## Light-years to feet table

*Common light-year values converted to feet.*

| Light-years | Feet |
| --- | --- |
| 1 ly | 3.1039142 × 10^16 |
| 2 ly | 6.2078284 × 10^16 |
| 3 ly | 9.3117426 × 10^16 |
| 4 ly | 1.2415657 × 10^17 |
| 5 ly | 1.5519571 × 10^17 |
| 10 ly | 3.1039142 × 10^17 |
| 15 ly | 4.6558713 × 10^17 |
| 20 ly | 6.2078284 × 10^17 |
| 25 ly | 7.7597855 × 10^17 |
| 30 ly | 9.3117426 × 10^17 |
| 40 ly | 1.2415657 × 10^18 |
| 50 ly | 1.5519571 × 10^18 |
| 75 ly | 2.3279356 × 10^18 |
| 100 ly | 3.1039142 × 10^18 |
| 250 ly | 7.7597855 × 10^18 |
| 500 ly | 1.5519571 × 10^19 |
| 1,000 ly | 3.1039142 × 10^19 |

## How the conversion works

The relationship is ft = ly × 3.103914197 × 10^16. Both units measure length, so the conversion is a fixed factor that never changes. The figure is exact rather than approximate: since the international yard and pound agreement of 1959, an inch is defined as exactly 25.4 millimetres and a pound as exactly 0.45359237 kilograms, and every other imperial and US customary unit here is derived from those two.

> Foot: Plural is "feet".

## Common questions

### How many feet are in one light-year?

One light-year equals 3.1039142 × 10^16 feet. ft = ly × 3.103914197 × 10^16.

### How do you convert light-years to feet?

Use ft = ly × 3.103914197 × 10^16. So 10 ly is 3.1039142 × 10^17 ft.

### How many light-years are in one foot?

One foot equals 3.222 × 10^-17 light-years, which is the reverse of the conversion above.

### Is there more than one kind of foot?

Plural is "feet".

## Related pages

- [Feet to Light-years](https://atoneplace.net/convert/feet-to-light-years/)
- [Light-years to Meters](https://atoneplace.net/convert/light-years-to-meters/)
- [Light-years to Kilometers](https://atoneplace.net/convert/light-years-to-km/)
- [Light-years to Centimeters](https://atoneplace.net/convert/light-years-to-cm/)
- [Light-years to Millimeters](https://atoneplace.net/convert/light-years-to-mm/)
- [Light-years to Miles](https://atoneplace.net/convert/light-years-to-miles/)
- [Light-years to Yards](https://atoneplace.net/convert/light-years-to-yards/)
- [Light-years to Inches](https://atoneplace.net/convert/light-years-to-inches/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)