# Millimeters to Chains (mm to ch)

Source: https://www.unitconvertercalculator.com/length/millimeters-to-chains/

**1 mm = 4.9709695378987E-5 ch**

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.

## Formula

Convert Millimeters to Chains

## Conversion Table

| Millimeters (mm) | Chains (ch) |
|---|---|
| 1 mm | 4.9709695378987E-5 ch |
| 10 mm | 0.00049709695378987 ch |
| 100 mm | 0.0049709695378987 ch |
| 1000 mm | 0.049709695378987 ch |
| 10000 mm | 0.49709695378987 ch |
| 20117 mm | 1.0000099419391 ch |
| 50000 mm | 2.4854847689493 ch |
| 100000 mm | 4.9709695378987 ch |
| 500000 mm | 24.854847689493 ch |
| 1000000 mm | 49.709695378987 ch |

## Units

### Millimeter (mm)

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

### 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.

## Background

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.

## Good to Know

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.

## FAQ

### 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.

## Non-Frequently Asked Questions

### How many paper clips span a chain?

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.

### How many grains of rice span a chain?

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.

### If Gunter had used millimeters, what would his chain be?

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.

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## See Also

- [Chains to Millimeters](https://www.unitconvertercalculator.com/length/chains-to-millimeters/)