Length and Area
mmtoch
Convert millimetres (mm) to chains (ch).
Factor1 mm = 4.97097e-5 ch
Converter
mm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
ch
Rendered to 6 significant figures.
Formula
Formula
ch = mm × 4.97097e-5
Multiply any value in millimetres by 4.97097e-5 to obtain the value in chains.
Worked example
Convert 100000 mm to ch.
- 01Start with 100000 mm.
- 02Multiply by the conversion factor: 100000 × 4.97097e-5 = 4.97097 ch.
Result100000 mm = 4.97097 ch
Conversion table
| mm | ch |
|---|---|
| 1 | 4.971e-5 |
| 2 | 9.9419e-5 |
| 5 | 0.00024855 |
| 10 | 0.0004971 |
| 20 | 0.00099419 |
| 50 | 0.0024855 |
| 100 | 0.004971 |
| 200 | 0.0099419 |
| 500 | 0.024855 |
| 1000 | 0.04971 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from mm to ch?
1 mm equals 4.97097e-5 ch. To convert, multiply the value in millimetres by 4.97097e-5.
How do I convert 1 mm to ch?
1 mm = 4.97097e-5 ch. For any value, multiply by 4.97097e-5.
How do I convert ch back to mm?
Divide by the same factor — or equivalently, multiply by 20116.8. So 1 ch = 20116.8 mm.
When would I need to convert millimetre to chain (Gunter's chain)?
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).