# Astronomical Units to Micrometers (au to μm)

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

**1 au = 1.495978707E+17 μm**

One astronomical unit equals approximately 1.496 x 1017 micrometers, or about 150 quadrillion micrometers. This conversion spans from planetary orbit scale to the cellular biology scale. A red blood cell at 7 micrometers is unfathomably small compared to the 149.6-million-km Earth-Sun distance.

## Formula

Convert Astronomical Units to Micrometers

## Conversion Table

| Astronomical Units (au) | Micrometers (μm) |
|---|---|
| 1.0E-15 au | 149.5978707 μm |
| 1.0E-14 au | 1495.978707 μm |
| 1.0E-13 au | 14959.78707 μm |
| 1.0E-12 au | 149597.8707 μm |
| 1.0E-11 au | 1495978.707 μm |
| 1.0E-10 au | 14959787.07 μm |
| 1.0E-9 au | 149597870.7 μm |
| 1.0E-8 au | 1495978707 μm |
| 1.0E-7 au | 14959787070 μm |
| 1.0E-6 au | 149597870700 μm |
| 1.0E-5 au | 1495978707000 μm |

## 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.

### Micrometer (μm)

One millionth of a meter, also called a micron. Used in biology for cell sizes, in engineering for surface finishes, and in manufacturing tolerances.

## Background

The Earth-Sun distance contains about 150 quadrillion micrometers. A human hair (75 micrometers) is 5 x 10-16 AU across. A bacterium at 1 micrometer is 6.7 x 10-18 AU. These numbers show why micrometers and AU belong to entirely different scientific domains.

## Good to Know

Micrometers are the language of biologists studying cells; AU is the language of astronomers studying planets. The conversion between them exists only to demonstrate the hierarchy of measurement scales.

## FAQ

### How many micrometers are in 1 AU?

One AU contains approximately 1.496 x 1017 micrometers (about 150 quadrillion). Since 1 AU = 149,597,870,700 m and 1 m = 106 micrometers, multiply.

### How do I convert AU to micrometers?

Multiply the AU value by 1.496 x 1017. For example, the Moon at 0.00257 AU is about 3.84 x 1014 micrometers from Earth.

### When is this conversion needed?

Almost never. Micrometers measure cells and semiconductor features. AU measures planetary orbits. The 17-order-of-magnitude gap means these units never meet in practice.

## Non-Frequently Asked Questions

### How many human cells span the Earth-Sun distance?

A typical human cell is about 20 um. 1 AU is about 1.496 x 1017 um. That is about 7.48 quadrillion cells in a line. Your body has 37 trillion cells - enough to span only 0.5% of the way to the Sun. You are cosmically tiny.

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## See Also

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