# Astronomical Units to Thou (au to thou)

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

**1 au = 5.8896799488189E+15 thou**

One astronomical unit equals approximately 5.890 x 1015 thou (mils), or about 5.9 quadrillion thou. The thou (0.001 inch / 25.4 micrometers) is used for precision engineering tolerances. The 15-order-of-magnitude gap between these units makes this conversion purely theoretical.

## Formula

Convert Astronomical Units to Thou

## Conversion Table

| Astronomical Units (au) | Thou (thou) |
|---|---|
| 1.0E-14 au | 58.896799488189 thou |
| 1.0E-13 au | 588.96799488189 thou |
| 1.0E-12 au | 5889.6799488189 thou |
| 1.0E-11 au | 58896.799488189 thou |
| 1.0E-10 au | 588967.99488189 thou |
| 1.0E-9 au | 5889679.9488189 thou |
| 1.0E-8 au | 58896799.488189 thou |
| 1.0E-7 au | 588967994.88189 thou |
| 1.0E-6 au | 5889679948.8189 thou |
| 1.0E-5 au | 58896799488.189 thou |
| 0.0001 au | 588967994881.89 thou |

## 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.

### Thou (thou)

One thousandth of an inch (0.0254 mm). Also called a mil in the US. Used in engineering, manufacturing, and for measuring thin materials like plastic film.

## Background

The Earth-Sun distance is about 5.9 quadrillion thou. A typical PCB copper foil at 1.4 thou is 2.4 x 10-16 AU thick. A human hair at 3 thou is 5.1 x 10-16 AU. These numbers show the absurd gap between engineering precision and astronomical distance.

## Good to Know

The thou survives in American electronics manufacturing, while the AU thrives in planetary science. Both are precision units in their domains, but a PCB designer and a planetary scientist would never need to compare notes in each other's units.

## FAQ

### How many thou are in 1 AU?

One AU contains approximately 5.890 x 1015 thou (about 5.9 quadrillion). Since 1 thou = 25.4 micrometers and 1 AU = 1.496 x 1017 micrometers, divide accordingly.

### How thick is 1 thou in AU?

One thou (0.001 inch / 25.4 micrometers) is approximately 1.698 x 10-16 AU. This is less than a quadrillionth of an AU.

### When would this conversion be used?

Never in practice. The thou is for engineering tolerances on PCBs, coatings, and thin materials. The AU is for planetary orbits. These measurement domains have no overlap.

## Non-Frequently Asked Questions

### How many paint coats thick is the Earth-Sun distance?

A coat of paint is about 2-4 thou (50-100 micrometers). The Earth-Sun distance is about 5.89 trillion thou. So roughly 1.5-3 trillion paint coats. Even the most patient painter would give up.

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## See Also

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