Millimeter is 0.001 meter units.
Millimeters to Chains Converter — mm to ch
Convert Millimeter (mm) to Chain (ch) using the exact conversion factor (1 millimeter = 0.0000497097 chain). See the formula, worked examples, conversion table, history, and common uses.
Millimeters to Chains converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
A surveyor's chain is 66 feet.
Result = input x 0.001 / 20.1168.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Millimeters to Chains
Millimeter and Chain both measure length. Millimeter is most often used for engineering drawings and manufacturing tolerances worldwide (including in the us).
Formula
chains = millimeters × 0.000049709695379
This factor comes from each unit's defined relationship to the category's base unit: 1 millimeter equals 0.001 base units, and 1 chain equals 20.1168 base units, so dividing one by the other gives the direct millimeter-to-chain factor of 0.000049709695379.
Simple example
1 mm × 0.00004970969538 = 0.0000497097 ch
1 millimeter = 0.0000497097 chains.
Real-world example
10 mm × 0.00004970969538 = 0.000497097 ch
10 millimeters = 0.000497097 chains.
Conversion table
| Millimeter (mm) | Chain (ch) |
|---|---|
| 1 mm | 0.0000497097 ch |
| 5 mm | 0.0002485485 ch |
| 10 mm | 0.000497097 ch |
| 21.0975 mm | 0.0010487503 ch |
| 42.195 mm | 0.0020975006 ch |
| 100 mm | 0.0049709695 ch |
Reverse conversion: Chain to Millimeter
0.0000497097 ch × 20116.8 = 1.000000093 mm
0.0000497097 chains = 1.000000093 millimeters.
millimeters = chains × 20116.8
For a page dedicated to this direction, see Chain to Millimeter.
Understanding the Millimeter
Millimeter (mm) measures distance. A millimeter is one-thousandth of a meter. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard small/precision length unit worldwide, including in US engineering and manufacturing
Uses of the Millimeter today
- Engineering drawings and manufacturing tolerances worldwide (including in the US)
- Rainfall measurement in most countries
- Small-scale everyday measurement (screen sizes, hardware)
History of the Millimeter
The millimeter follows from the meter via the 'milli-' SI prefix (10⁻³). It is notable as one of the few metric units in routine US technical/engineering use, since precision manufacturing and electronics are often specified in millimeters even in the US.
Historical origin. Millimeter was not the invention of a single named person; it developed through the process described above.
Understanding the Chain (ch)
A surveyor's chain is 66 feet.
Millimeter — sources
- BIPM SI Brochure — SI prefixes — Defines 'milli-' as the prefix for 10⁻³.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many chains are in 1 millimeter?
1 millimeter equals 0.0000497097 chains, using the exact defined conversion factor rather than an estimate.
How do I convert millimeter to chain?
Multiply the millimeter value by 0.00004970969538. The converter above does this instantly to whatever precision you set.
How do I convert chain back to millimeter?
Use the reverse factor: 1 chain equals 20,116.8 millimeters. You can also use the swap control in the converter above to flip the direction instantly.
What is a millimeter?
Millimeter (mm) measures distance. A millimeter is one-thousandth of a meter. It is classified as a SI derived (metric prefix) unit.
What is a chain?
Chain (ch) is a unit of length.
Is the millimeter to chain conversion exact?
Yes. Both millimeter and chain are defined by fixed standards rather than physical artifacts, so the factor of 0.00004970969538 used above is exact to as many digits as you choose to display.
Where is the millimeter still used today?
Standard small/precision length unit worldwide, including in US engineering and manufacturing