A surveyor's chain is 66 feet.
Chains to Fathoms Converter — ch to ftm
Convert Chain (ch) to Fathom (ftm) using the exact conversion factor (1 chain = 11 fathom). See the formula, worked examples, and conversion table.
Chains to Fathoms converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
A fathom is six feet.
Result = input x 20.1168 / 1.8288.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Chains to Fathoms
Chain and Fathom both measure length. Specifically: A surveyor's chain is 66 feet, and a fathom is six feet.
Formula
fathoms = chains × 11
This factor comes from each unit's defined relationship to the category's base unit: 1 chain equals 20.1168 base units, and 1 fathom equals 1.8288 base units, so dividing one by the other gives the direct chain-to-fathom factor of 11.
Simple example
1 ch × 11 = 11 ftm
1 chain = 11 fathoms.
Real-world example
10 ch × 11 = 110 ftm
10 chains = 110 fathoms.
Conversion table
| Chain (ch) | Fathom (ftm) |
|---|---|
| 1 ch | 11 ftm |
| 5 ch | 55 ftm |
| 10 ch | 110 ftm |
| 21.0975 ch | 232.0725 ftm |
| 42.195 ch | 464.145 ftm |
| 100 ch | 1,100 ftm |
Reverse conversion: Fathom to Chain
11 ftm × 0.09090909091 = 1 ch
11 fathoms = 1 chain.
chains = fathoms × 0.0909090909091
For a page dedicated to this direction, see Fathom to Chain.
Understanding the Chain (ch)
A surveyor's chain is 66 feet.
Understanding the Fathom (ftm)
A fathom is six feet.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many fathoms are in 1 chain?
1 chain equals 11 fathoms, using the exact defined conversion factor rather than an estimate.
How do I convert chain to fathom?
Multiply the chain value by 11. The converter above does this instantly to whatever precision you set.
How do I convert fathom back to chain?
Use the reverse factor: 1 fathom equals 0.0909090909 chains. You can also use the swap control in the converter above to flip the direction instantly.
What is a chain?
Chain (ch) is a unit of length.
What is a fathom?
Fathom (ftm) is a unit of length.
Is the chain to fathom conversion exact?
Yes. Both chain and fathom are defined by fixed standards rather than physical artifacts, so the factor of 11 used above is exact to as many digits as you choose to display.