# Chains to Thou (ch to thou)

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

**1 ch = 792000 thou**

One chain equals exactly 792,000 thou (mils). Since 1 chain = 792 inches and 1 inch = 1,000 thou, the math is 792 x 1,000 = 792,000. This conversion connects the land surveying chain with the precision engineering unit used for thin coatings, wire gauges, and PCB specifications.

## Formula

Convert Chains to Thou

## Conversion Table

| Chains (ch) | Thou (thou) |
|---|---|
| 1.0E-6 ch | 0.792 thou |
| 1.0E-5 ch | 7.92 thou |
| 0.0001 ch | 79.2 thou |
| 0.001 ch | 792 thou |
| 0.01 ch | 7920 thou |
| 0.1 ch | 79200 thou |
| 0.5 ch | 396000 thou |
| 1 ch | 792000 thou |
| 5 ch | 3960000 thou |
| 10 ch | 7920000 thou |
| 50 ch | 39600000 thou |
| 100 ch | 79200000 thou |

## Units

### Chain (ch)

Exactly 66 feet or 4 rods (20.1168 m). Invented by Edmund Gunter for land surveying. 80 chains make one mile. Still used in US public land surveys.

### 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 cricket pitch (1 chain) is 792,000 thou. A PCB copper trace at 6 thou is 7.58 x 10-6 chains. These units never meet in practice: chains measure fields, thou measures circuit board features. The conversion exists for mathematical completeness only.

## Good to Know

The thou (0.001 inch) was born from the Industrial Revolution's need for precision. The chain (66 feet) was born from the Agricultural Revolution's need for land measurement. Two revolutions, two units, no overlap.

## FAQ

### How many thou are in 1 chain?

One chain contains exactly 792,000 thou (mils). Since 1 chain = 792 inches and 1 inch = 1,000 thou, multiply 792 by 1,000.

### How do I convert chains to thou?

Multiply the number of chains by 792,000. For example, 0.5 chains = 396,000 thou.

### Is this conversion practical?

No. Chains measure land parcels. Thou measures thin coatings and PCB traces. They belong to entirely separate measurement domains.

## Non-Frequently Asked Questions

### Is a thou of chain the same as a thousandth of an inch of chain?

Yes. One thou is 1/1000 of an inch. A chain is 792 inches or 792,000 thou. One thou of chain is 0.0254 mm - the width of a fine scratch on one of Gunter's chain links. Even measurement tools have measurement tolerances.

### Did PCB designers ever need to know about chains?

No. PCB designers use thou (mils) for trace widths and chains measure farm fields. The closest these professions get is when a PCB factory is built on a chain-surveyed plot of land. The building is measured in chains; its products are measured in thou.

### How many PCB traces fit across a chain?

A chain is 792,000 thou. A standard PCB trace is about 6 thou wide. So about 132,000 traces fit across one chain. That is more traces than any circuit board has ever needed, but it puts the chain's length in electronics perspective.

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## See Also

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