# Parsecs to Thou (pc to thou)

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

**1 pc = 1.2148336935005E+21 thou**

One parsec equals approximately 1.215 x 1021 thou (about 1.2 sextillion mils). The parsec measures stellar distances; the thou measures American precision engineering. About 21 orders of magnitude separate star-mapping from machining.

## Formula

Convert Parsecs to Thou

## Conversion Table

| Parsecs (pc) | Thou (thou) |
|---|---|
| 1.0E-21 pc | 0 thou |
| 1.0E-20 pc | 12.148336935005 thou |
| 1.0E-19 pc | 121.48336935005 thou |
| 1.0E-18 pc | 1214.8336935005 thou |
| 1.0E-17 pc | 12148.336935005 thou |
| 1.0E-16 pc | 121483.36935005 thou |
| 1.0E-15 pc | 1214833.6935005 thou |
| 1.0E-14 pc | 12148336.935005 thou |
| 1.0E-13 pc | 121483369.35005 thou |
| 1.0E-12 pc | 1214833693.5005 thou |
| 1.0E-11 pc | 12148336935.005 thou |

## Units

### Parsec (pc)

The distance at which one astronomical unit subtends an angle of one arcsecond. Approximately 3.26 light-years or 30.857 trillion kilometers. The standard unit in professional astronomy.

### 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

A parsec is about 1.2 sextillion thou. A 1-thou tolerance (25.4 um) is 8.23 x 10-22 parsecs. The precision gap between a machinist's finest work and an astronomer's measurement scale is 21 orders of magnitude.

## Good to Know

The thou and parsec represent the two ends of American precision: the thou measures the finest tolerances in American workshops; the parsec measures the largest distances in American observatories. Both are essential American measurement units. Both require years of training to use properly.

## FAQ

### How many thou are in 1 parsec?

One parsec contains approximately 1.215 x 1021 thou.

### How many parsecs is 1 thou?

One thou equals approximately 8.232 x 10-22 parsecs.

### Is this conversion used?

Never. American precision engineering and stellar astronomy exist in completely different measurement worlds.

## Non-Frequently Asked Questions

### How many precision-machined parts span 1 parsec?

A typical machined part is 1,000 thou (1 inch = 25.4 mm). 1 parsec (1.215 x 1021 thou) = about 1.215 x 1018 parts. All manufactured parts in human history (maybe 1014) would span about 10-7 parsecs. All human manufacturing covers one ten-millionth of a parsec.

### Is the thou or the parsec more useful?

Both are essential to their professions. Without the thou, precision machining fails. Without the parsec, stellar astronomy cannot communicate. Neither could replace the other. Usefulness depends entirely on whether you are building an engine or mapping a galaxy.

### If a machinist's tolerance were applied at parsec scale, what would it look like?

A typical machining tolerance is 1 thou (25.4 um). At parsec scale, 1 thou tolerance would mean stellar positions known to 8.23 x 10-22 parsecs = about 0.025 mm at 30 trillion km distance. Modern astrometry (Gaia satellite) achieves about 10 microarcsecond precision = about 10-9 parsecs. Machinists are 1013 times more precise than astronomers. But machinists work 1016 times closer to their workpiece.

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## See Also

- [Thou to Parsecs](https://www.unitconvertercalculator.com/length/thou-to-parsecs/)