# Astronomical Units to Feet (au to ft)

Source: https://www.unitconvertercalculator.com/length/astronomical-units-to-feet/

**1 au = 490806662401.57 ft**

One astronomical unit equals approximately 4.908 x 1011 feet, or about 491 billion feet. This conversion expresses the Earth-Sun distance in the everyday American length unit. While the number is enormous, it helps Americans conceptualize astronomical distances in units they understand intuitively.

## Formula

Convert Astronomical Units to Feet

## Conversion Table

| Astronomical Units (au) | Feet (ft) |
|---|---|
| 1.0E-10 au | 49.080666240157 ft |
| 1.0E-9 au | 490.80666240157 ft |
| 1.0E-8 au | 4908.0666240157 ft |
| 1.0E-7 au | 49080.666240157 ft |
| 1.0E-6 au | 490806.66240157 ft |
| 1.0E-5 au | 4908066.6240157 ft |
| 0.0001 au | 49080666.240157 ft |
| 0.001 au | 490806662.40157 ft |
| 0.01 au | 4908066624.0157 ft |
| 0.1 au | 49080666240.157 ft |
| 1 au | 490806662401.57 ft |

## Units

### Astronomical Unit (au)

Exactly 149,597,870,700 meters by IAU 2012 definition. Roughly the average distance from the Earth to the Sun. Used for distances within our solar system.

### Foot (ft)

An imperial unit of length equal to 12 inches or 0.3048 meters. Used in the US and UK for height, altitude, and construction.

## Background

The Earth-Sun distance of 1 AU is about 491 billion feet. A commercial airplane cruising at 35,000 feet is at 0.0000000234 AU altitude. The Moon at about 1.26 million feet from Earth is only 0.00257 AU away. These comparisons help put solar system distances into perspective for people who think in feet.

## Good to Know

American aviation uses feet for altitude, but space missions switch to kilometers or AU once past the atmosphere. The transition from feet to AU happens roughly at the boundary between aviation and space exploration, around 100 km (328,000 feet) altitude.

## FAQ

### How many feet are in 1 AU?

One AU contains approximately 4.908 x 1011 feet (about 491 billion feet). This derives from 1 AU = 149,597,870,700 meters x 3.28084 feet/meter.

### How far is the Moon in AU?

The Moon is about 1,261,000 feet (238,855 miles / 384,400 km) from Earth, which equals approximately 0.00257 AU. The Moon is very close on the astronomical scale.

### Is this conversion used in aerospace?

Rarely. Aerospace engineers use feet for aircraft altitude and AU or kilometers for orbital distances. The conversion might appear when comparing aircraft altitude with satellite orbital distances for educational purposes.

## Non-Frequently Asked Questions

### How many steps to the Sun?

Average step is about 2.5 feet. One AU is about 4.908 x 1011 feet, so roughly 196 billion steps. At 5,000 steps per day (the average), it would take about 107,000 years of walking. Pack sunscreen. And a sandwich. And several evolutionary epochs.

### If the Sun were a football field away, how big would Earth be?

If the Earth-Sun distance (1 AU) shrank to a football field (300 feet), Earth would be about 0.003 inches across - smaller than the period at the end of this sentence. The Sun would be about 0.35 inches, the size of a pea. Football is not the right sport for astronomy.

### Is space measured in feet anywhere?

Aircraft altitude is measured in feet up to about 60,000 feet. Above that, space is measured in kilometers, AU, and parsecs. The foot stops being useful at roughly the boundary between atmosphere and space. Feet are grounded - literally.

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## See Also

- [Feet to Astronomical Units](https://www.unitconvertercalculator.com/length/feet-to-astronomical-units/)