Science Constants - Chain Symbol: ch Value: 20.1168 m Category: - Units of Length Description: The chain is an obsolete unit of length used by British surveyors. The value given above is Gunter's Chain.   1 chain (Gunter's) = 1/10 furlong 1 chain (Gunter's) = 4 rods 1 chain (Gunter's) = 66 feet 1 chain (Gunter's) = 100 links   Other values for the chain: Engineer's Chain: 30.48 m Ramsden's Chain: 30.48 m Surveyor's Chain: 20.1168 m