What Is Chain?
A chain is an old unit used to measure length on land. One chain is equal to 66 feet, or about 20 meters. It is mainly used in surveying, map making, and measuring fields and property lines.
In this page, chain always means the measuring unit, not the metal chain you wear or use to pull things.
Definition
A chain is a unit of length with these common values:
- 1 chain = 66 feet
- 1 chain = 22 yards
- 1 chain = 4 rods or 4 poles or 4 perches
- 1 chain = 100 links
- 1 chain ≈ 20.1168 meters in the international system
In simple words, a chain is a bit longer than 20 meters, or about the length of a small swimming pool.
History / Origin
The chain unit comes from land surveying in England in the early 1600s. An English clergyman and mathematician named Edmund Gunter created a special measuring chain for surveyors. This tool was called Gunter’s chain.
Gunter’s chain:
- Was made of metal links
- Was exactly 66 feet long
- Had 100 small links, so each link was 0.66 feet long
The chain was chosen so that land area could be calculated easily in acres. Because of this, chain quickly became a standard unit for measuring land in Britain and later in many other countries, especially those that used British systems.
Symbol & Abbreviation
The most common symbols for chain are:
- ch for chain, used in surveying and maps
- chn sometimes used to avoid confusion
Example: 5 ch means 5 chains.
Current Use Around the World
Today, the chain is not an official SI unit, but it is still found in some special fields and in older records.
Typical modern uses include:
- Land surveying Some surveyors still use chain based units when working with older plans.
- Property and farm maps Old farm sizes and property boundaries in countries like the United Kingdom, the United States, Canada, Australia, New Zealand, and India were often measured in chains.
- Railways In some rail systems, distances along the track were marked in miles and chains.
- Cricket A cricket pitch is 22 yards long, which is exactly 1 chain.
Most daily measurements now use meters or feet, but chain still matters when reading old documents, maps, and engineering records.
Example Conversions
Here are some easy examples showing how to convert chains to other units:
- Chains to feet
1 chain = 66 feet
3 chains = 3 × 66 = 198 feet
10 chains = 10 × 66 = 660 feet - Chains to yards
1 chain = 22 yards
2 chains = 44 yards
5 chains = 110 yards - Chains to meters (approximate)
1 chain ≈ 20.12 m
2 chains ≈ 40.23 m
5 chains ≈ 100.58 m
10 chains ≈ 201.17 m - Chains to miles
80 chains = 1 mile
40 chains = 0.5 mile
8 chains = 0.1 mile - Chains to links
1 chain = 100 links
0.5 chain = 50 links
Quick tips:
- To get feet from chains, multiply by 66.
- To get meters from chains, multiply by about 20.12.
Related Units
Chain is closely linked with these other length units:
- Link The small part of a chain.
1 chain = 100 links. - Rod, pole, or perch Old land units that mean the same thing.
1 chain = 4 rods. - Furlong Used for race tracks and fields.
1 furlong = 10 chains. - Mile Common long distance unit.
1 mile = 80 chains. - Foot Basic imperial length unit.
1 chain = 66 feet. - Yard 3 feet.
1 chain = 22 yards. - Meter Main SI length unit.
1 chain ≈ 20.1168 meters.
FAQs
What is a chain in simple words?
A chain is an old unit for measuring distance on land. One chain is 66 feet or about 20 meters long.
Why is a chain 66 feet long?
The length 66 feet was chosen so that land area in acres was easy to work out. With this length, a rectangle 10 chains by 1 chain has an area of 1 acre.
Is chain still used today?
Yes, but not very often. It is mostly used in old maps, property records, railways, and by some surveyors who work with historic measurements.
How many chains are in a mile?
There are 80 chains in 1 mile.
How many meters are in 1 chain?
One chain is about 20.1168 meters. For quick mental math, many people round it to 20.1 meters or just 20 meters.
What is the symbol for chain?
The usual symbol is ch. For example, 7 ch means 7 chains.
Is chain an SI unit?
No. The SI system uses the meter as the main unit of length. Chain is an older non SI unit, but it is still recognized in surveying and mapping.
Is the measuring chain the same as a metal chain used for pulling?
No. The word is the same, but in measurement, a chain is a unit of length. It was once measured using a special metal tool called Gunter’s chain, but today the unit is usually used only on paper or in calculations.