Length and Area
chtomm
Convert chains (ch) to millimetres (mm).
Factor1 ch = 20116.8 mm
Converter
ch
Accepts numbers or expressions, e.g. 150 + 14.7
Result
mm
Rendered to 6 significant figures.
Formula
Formula
mm = ch × 20116.8
Multiply any value in chains by 20116.8 to obtain the value in millimetres.
Worked example
Convert 1 ch to mm.
- 01Start with 1 ch.
- 02Multiply by the conversion factor: 1 × 20116.8 = 20116.8 mm.
Result1 ch = 20116.8 mm
Conversion table
| ch | mm |
|---|---|
| 1 | 20117 |
| 2 | 40234 |
| 5 | 1.0058e+5 |
| 10 | 2.0117e+5 |
| 20 | 4.0234e+5 |
| 50 | 1.0058e+6 |
| 100 | 2.0117e+6 |
| 200 | 4.0234e+6 |
| 500 | 1.0058e+7 |
| 1000 | 2.0117e+7 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from ch to mm?
1 ch equals 20116.8 mm. To convert, multiply the value in chains by 20116.8.
How do I convert 1 ch to mm?
1 ch = 20116.8 mm. For any value, multiply by 20116.8.
How do I convert mm back to ch?
Divide by the same factor — or equivalently, multiply by 4.97097e-5. So 1 mm = 4.97097e-5 ch.
When would I need to convert chain (Gunter's chain) to millimetre?
Length conversions appear in piping, layout, and mechanical drawings — particularly when reconciling imperial fittings or instrument lengths with metric plant drawings.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).