How many millimeters are in 1 chain?

One chain equals exactly 20,116.8 millimeters. Since 1 chain = 20.1168 meters and 1 meter = 1,000 mm, multiply 20.1168 by 1,000.

How do I convert chains to millimeters?

Multiply the number of chains by 20,116.8. For example, 3 chains = 3 x 20,116.8 = 60,350.4 mm.

When would I need millimeter precision for chains?

When placing boundary markers or monuments with surveying instruments that read in millimeters. Modern total stations and GPS units output in meters/millimeters, so old chain measurements need conversion to this precision level.

Chains to Millimeters (ch to mm) Converter

1 ch = 20,116.8 mm

1 Chain equals 20,116.8 Millimeters (1 ch = 20,116.8 mm). Convert Chains to Millimeters with formula, table, and examples.

One chain equals exactly 20,116.8 millimeters (about 20.1 meters). This conversion connects the historical land surveying chain with the modern precision unit used in engineering and manufacturing. Converting chains to millimeters is occasionally needed when old survey measurements must be expressed in fine metric detail.

How to Convert Chains to Millimeters

mm = ch × 20,116.8

Multiply the value in Chains by 20,116.8

Take your value in Chains
Multiply by 20,116.8
Read the result in Millimeters

Common Chains to Millimeters Conversions

Chains (ch)	Millimeters (mm)	Status
0.01 ch	201.168 mm
0.05 ch	1,005.84 mm
0.1 ch	2,011.68 mm
0.25 ch	5,029.2 mm
0.5 ch	10,058.4 mm
1 ch	20,116.8 mm
2 ch	40,233.6 mm
5 ch	100,584 mm
10 ch	201,168 mm
20 ch	402,336 mm
40 ch	804,672 mm
80 ch	1,609,344 mm
100 ch	2,011,680 mm

Good to Know About Chains to Millimeters Conversion

Modern surveying uses millimeter-precision GPS and total stations, but the boundaries they measure were often originally set in chains and links. The conversion from 17th-century chains to 21st-century millimeters bridges 400 years of measurement technology.

Chains to Millimeters: What You Need to Know

A cricket pitch (1 chain) is 20,116.8 mm. One link (1/100 of a chain) is 201.168 mm, or about 7.92 inches. When restoring historical boundary markers to millimeter precision, this conversion becomes relevant. Most practical applications would use meters rather than millimeters for chain-scale distances.

What is a Chain? ch

Exactly 66 feet or 4 rods (20.1168 m). Invented by Edmund Gunter for land surveying. 80 chains make one mile. Still used in US public land surveys.

Imperial land surveying US public land

Learn more about Chain →

What is a Millimeter? mm

A metric unit of length equal to one thousandth of a meter. Used in engineering, manufacturing, and precise measurements.

Metric engineering manufacturing rainfall

Learn more about Millimeter →

Going the other way? Use our Millimeters to Chains converter.

Chains to Millimeters FAQ

One chain equals exactly 20,116.8 millimeters. Since 1 chain = 20.1168 meters and 1 meter = 1,000 mm, multiply 20.1168 by 1,000.
Multiply the number of chains by 20,116.8. For example, 3 chains = 3 x 20,116.8 = 60,350.4 mm.
When placing boundary markers or monuments with surveying instruments that read in millimeters. Modern total stations and GPS units output in meters/millimeters, so old chain measurements need conversion to this precision level.

Non-Frequently Asked Questions About Chains to Millimeters

Questions nobody should ask - but someone did.

A chain is 20,116.8 mm long. One millimeter of rain on a 1-chain road that is 4 meters wide covers 20,116.8 x 4,000 = 80.5 million square millimeters, or 80.5 liters of water. Even a light drizzle deposits serious water on a chain of road.
For surveying, yes. A chain measured to the nearest millimeter (0.005% precision) would satisfy any modern land survey. Old surveyors working with physical chains were lucky to get within 10 mm (half an inch) accuracy.
Wire is sold in meters or feet, not chains. A chain-length (20.1168 m) of standard copper wire costs about 3 euros. The hardware store clerk will not know what a chain is, but they can cut 20.12 meters without blinking.