What Is Square Chain?
A square chain is a unit used to measure area, mainly for land. It is based on the surveyor’s chain, which is a length unit. When you make a square where each side is one chain long, the space inside that square is one square chain.
Square chains were common in old land surveys and farm maps. Today they are mostly used when reading or converting older land records.
Definition
A square chain is the area of a square that is one chain long on each side.
- 1 chain = 66 feet = 22 yards ≈ 20.1168 meters
- 1 square chain = 66 ft × 66 ft = 4,356 square feet
- 1 square chain = 22 yd × 22 yd = 484 square yards
- 1 square chain ≈ 404.6856 square meters
- 1 square chain = 0.1 acre (one tenth of an acre)
- 1 square chain ≈ 0.04047 hectare
So, ten square chains make exactly one acre.
History / Origin
The square chain comes from land surveying in countries that used the old British measurement system.
The length unit called the chain was made popular in the early 1600s by Edmund Gunter, a mathematician and surveyor. His metal chain was used to measure land for farms, taxes, and maps. Because surveyors already used the chain for length, it was natural to use a square based on that length for area. That square became the square chain.
Over time, the acre was officially linked to the chain. One acre was defined as ten square chains. This made it very easy for surveyors to measure and record land areas using chains and links.
Symbol & Abbreviation
Square chain can be written in a few short forms:
- ch² – most common symbol
- sq ch – reads as square chain
- square ch – sometimes used in older documents
Modern technical writing often prefers ch², but in plain text records you may see sq ch or square chain written out fully.
Current Use Around the World
Today, the square chain is not widely used in everyday life. Most countries now use metric units like square meters and hectares for land area. However, square chains still appear in some places:
- United Kingdom – in older deeds and historic land surveys
- United States – in some old farm records and boundary descriptions
- Australia and New Zealand – in early 1900s town plans and rural surveys
- Other former British territories – in older land documents that have not been updated to metric units
Modern surveyors usually convert square chains to acres, hectares, or square meters when updating or comparing land records.
Example Conversions
Here are some simple examples to help you understand square chain conversions.
1 square chain to other units
- 1 square chain = 4,356 square feet
- 1 square chain = 484 square yards
- 1 square chain ≈ 404.69 square meters
- 1 square chain = 0.1 acre
- 1 square chain ≈ 0.04047 hectare
Square chains to acres
- 5 square chains = 0.5 acre
- 10 square chains = 1 acre
- 20 square chains = 2 acres
- 25 square chains = 2.5 acres
Rule: divide square chains by 10 to get acres.
Square chains to hectares
- 1 square chain ≈ 0.04047 hectare
- 10 square chains ≈ 0.4047 hectare
- 25 square chains ≈ 1.012 hectare
Rule: multiply square chains by about 0.04047 to get hectares.
Square chains to square meters
- 1 square chain ≈ 404.69 m²
- 2 square chains ≈ 809.37 m²
- 10 square chains ≈ 4,046.86 m²
Rule: multiply square chains by about 404.69 to get square meters.
Related Units
Square chain is part of a family of land and length units used in old British and surveying systems.
- Chain (ch) – length unit, 1 chain = 66 feet ≈ 20.1168 meters
- Link – small length unit, 100 links = 1 chain
- Square foot (ft²) – small area unit, 4,356 ft² = 1 square chain
- Square yard (yd²) – medium area unit, 484 yd² = 1 square chain
- Rood – land area unit, 1 rood = 2.5 square chains = 0.25 acre
- Acre – common land unit, 1 acre = 10 square chains
- Square meter (m²) – metric area unit, used worldwide today
- Hectare (ha) – metric land unit, 1 ha = 10,000 m² ≈ 24.71 square chains
FAQs
What is a square chain in simple words?
A square chain is the area of a square where each side is one chain long. It is an old way to measure land and equals one tenth of an acre.
How many square chains are in one acre?
There are 10 square chains in one acre. So if you know the area in square chains, divide by 10 to get acres.
How big is 1 square chain in square feet?
One square chain covers 4,356 square feet. That is the same as a square that is 66 feet long on each side.
Is a chain the same as a square chain?
No. A chain is a unit of length. A square chain is a unit of area. You make a square chain by forming a square that is one chain by one chain.
Do people still use square chains today?
Square chains are rarely used in new work. However, they still appear in old farm maps, town plans, and land deeds, especially in countries that once used the British system.
How do I convert square chains to hectares?
To change square chains to hectares, multiply by about 0.04047. For example, 20 square chains × 0.04047 ≈ 0.81 hectares.
Why is the square chain important in history?
The square chain helped surveyors measure and divide land in a regular way. It linked the chain length to the acre area, which made land taxes and ownership records easier to handle.
