# Chains to Fathoms (ch to ftm)

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

**1 ch = 11 ftm**

One chain equals exactly 11 fathoms. Both units come from the English measurement tradition: the chain (66 feet) for land surveying and the fathom (6 feet) for maritime depth. The clean ratio of 11:1 reflects their shared heritage in the English foot system.

## Formula

Convert Chains to Fathoms

## Conversion Table

| Chains (ch) | Fathoms (ftm) |
|---|---|
| 0.1 ch | 1.1 ftm |
| 0.25 ch | 2.75 ftm |
| 0.5 ch | 5.5 ftm |
| 1 ch | 11 ftm |
| 2 ch | 22 ftm |
| 5 ch | 55 ftm |
| 10 ch | 110 ftm |
| 20 ch | 220 ftm |
| 40 ch | 440 ftm |
| 80 ch | 880 ftm |
| 100 ch | 1100 ftm |
| 200 ch | 2200 ftm |
| 500 ch | 5500 ftm |
| 1000 ch | 11000 ftm |

## 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.

### Fathom (ftm)

Exactly 6 feet (1.8288 m). Traditionally used to measure water depth in nautical contexts. Originally based on the span of outstretched arms.

## Background

Since 1 chain = 66 feet and 1 fathom = 6 feet, the ratio is exactly 66/6 = 11. Ten chains (1 furlong) equals 110 fathoms. This is one of the few chain conversions that yields a clean whole number, thanks to both units being defined as exact multiples of the foot.

## Good to Know

The chain and fathom both emerged from the same English measurement tradition but diverged into different domains: land and sea. Their 11:1 ratio is a remnant of the coherent imperial system where all units were defined in feet.

## FAQ

### How many fathoms are in 1 chain?

One chain equals exactly 11 fathoms. This clean ratio exists because both are defined in feet: 1 chain = 66 feet, 1 fathom = 6 feet, and 66/6 = 11.

### How do I convert chains to fathoms?

Multiply the number of chains by 11. For example, 5 chains = 55 fathoms. The conversion is exact with no rounding needed.

### Are chains and fathoms related historically?

Both derive from the English foot-based measurement system. The chain was designed for land surveying (66 feet = 4 rods), while the fathom was designed for measuring water depth (the span of outstretched arms, roughly 6 feet). They share the foot as their common ancestor.

## Non-Frequently Asked Questions

### Could a sailor use a chain to measure depth?

Technically a chain is 11 fathoms, so you could lower one into water and count. But sailors used lead lines, not 20-meter metal chains. A chain sinking to the bottom would be hard to retrieve and terrible for your back.

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## See Also

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