How many chains is 1 millimeter?

One millimeter equals approximately 4.971 x 10-5 chains (about 1/20,117).

How many millimeters are in 1 chain?

One chain contains approximately 20,116.8 mm.

When is this conversion needed?

When importing historical chain-based survey data into modern metric engineering drawings or GIS databases that use millimeters.

Millimeters to Chains (mm to ch) Converter

1 mm = 0.00005 ch

1 Millimeter equals 0.00005 Chains (1 mm = 0.00005 ch). Convert Millimeters to Chains with formula, table, and examples.

One millimeter equals approximately 4.971 x 10^-5 chains, or about 1/20,117 of a chain. A chain (20,116.8 mm) contains about 20,117 millimeters. The millimeter measures precision engineering; the chain measures English land parcels.

How to Convert Millimeters to Chains

ch = mm × 0.0000497097

Multiply the value in Millimeters by 0.0000497097

Take your value in Millimeters
Multiply by 0.0000497097
Read the result in Chains

Common Millimeters to Chains Conversions

Millimeters (mm)	Chains (ch)	Status
1 mm	0.00005 ch
10 mm	0.0005 ch
100 mm	0.005 ch
1,000 mm	0.0497 ch
10,000 mm	0.4971 ch
20,117 mm	1 ch
50,000 mm	2.4855 ch
100,000 mm	4.971 ch
500,000 mm	24.8548 ch
1,000,000 mm	49.7097 ch

Good to Know About Millimeters to Chains Conversion

The millimeter will outlive the chain. One is the international standard for engineering; the other is a 400-year-old relic. But old chain-based property records still define legal boundaries in many countries. The millimeter translates those records into modern precision.

Millimeters to Chains: What You Need to Know

A chain is about 20,117 mm. A 25 mm bolt is 0.00124 chains. When digitizing old English surveys into metric CAD systems, chain measurements are converted to millimeters for engineering precision.

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 →

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 →

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

Millimeters to Chains FAQ

One millimeter equals approximately 4.971 x 10^-5 chains (about 1/20,117).
One chain contains approximately 20,116.8 mm.
When importing historical chain-based survey data into modern metric engineering drawings or GIS databases that use millimeters.

Non-Frequently Asked Questions About Millimeters to Chains

Questions nobody should ask - but someone did.

A standard paper clip is about 33 mm long. A chain (20,117 mm) fits about 610 paper clips. During a truly boring meeting, 610 paper clips could be linked into a chain roughly the length of an actual surveyor's chain. Office supplies and surveying equipment converge.
A grain of rice is about 7 mm long. A chain (20,117 mm) fits about 2,874 grains. One cup of rice contains about 9,000 grains. So about 1/3 cup of rice, laid end-to-end, spans a cricket pitch. Surprisingly economical.
Gunter's chain was 66 feet = 20,116.8 mm. If he had specified it in millimeters, he would have said 'a chain of 20,117 millimeters with 100 links of 201.17 mm each.' This is more precise but less poetic. Surveyors chose poetry. Engineers chose precision. Both were right.