A fathom is six feet.
Fathoms to Chains Converter — ftm to ch
Convert Fathom (ftm) to Chain (ch) using the exact conversion factor (1 fathom = 0.0909090909 chain). See the formula, worked examples, and conversion table.
Fathoms to Chains 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 surveyor's chain is 66 feet.
Result = input x 1.8288 / 20.1168.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Fathoms to Chains
Fathom and Chain both measure length. Specifically: A fathom is six feet, and a surveyor's chain is 66 feet.
Formula
chains = fathoms × 0.0909090909091
This factor comes from each unit's defined relationship to the category's base unit: 1 fathom equals 1.8288 base units, and 1 chain equals 20.1168 base units, so dividing one by the other gives the direct fathom-to-chain factor of 0.0909090909091.
Simple example
1 ftm × 0.09090909091 = 0.0909090909 ch
1 fathom = 0.0909090909 chains.
Real-world example
10 ftm × 0.09090909091 = 0.9090909091 ch
10 fathoms = 0.9090909091 chains.
Conversion table
| Fathom (ftm) | Chain (ch) |
|---|---|
| 1 ftm | 0.0909090909 ch |
| 5 ftm | 0.4545454545 ch |
| 10 ftm | 0.9090909091 ch |
| 21.0975 ftm | 1.917954545 ch |
| 42.195 ftm | 3.835909091 ch |
| 100 ftm | 9.090909091 ch |
Reverse conversion: Chain to Fathom
0.0909090909 ch × 11 = 0.9999999999 ftm
0.0909090909 chains = 0.9999999999 fathoms.
fathoms = chains × 11
For a page dedicated to this direction, see Chain to Fathom.
Understanding the Fathom (ftm)
A fathom is six feet.
Understanding the Chain (ch)
A surveyor's chain is 66 feet.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many chains are in 1 fathom?
1 fathom equals 0.0909090909 chains, using the exact defined conversion factor rather than an estimate.
How do I convert fathom to chain?
Multiply the fathom value by 0.09090909091. The converter above does this instantly to whatever precision you set.
How do I convert chain back to fathom?
Use the reverse factor: 1 chain equals 11 fathoms. You can also use the swap control in the converter above to flip the direction instantly.
What is a fathom?
Fathom (ftm) is a unit of length.
What is a chain?
Chain (ch) is a unit of length.
Is the fathom to chain conversion exact?
Yes. Both fathom and chain are defined by fixed standards rather than physical artifacts, so the factor of 0.09090909091 used above is exact to as many digits as you choose to display.