Chain Length Calculator
Calculate roller chain length in links from sprocket tooth counts, chain pitch, and center distance.
Enter your values
Sprocket tooth counts, chain pitch, and target center distance.
How this calculator works
Chain length is expressed in number of pitches (links). With center distance, pitch, and both sprocket tooth counts, the standard formula is:
The result is a theoretical number of links, which is then rounded up to the nearest whole number — and preferably to an even number, so the chain closes with a standard (rather than offset) connecting link.
Common chain pitch sizes (ANSI/ISO roller chain)
| Chain number | Pitch |
|---|---|
| ANSI 40 / ISO 08B | 12.70 mm |
| ANSI 50 / ISO 10B | 15.875 mm |
| ANSI 60 / ISO 12B | 19.05 mm |
| ANSI 80 / ISO 16B | 25.40 mm |
Frequently asked questions
Do I need to adjust center distance after rounding link count?
Yes — once you round to a whole (even) number of links, recompute the actual resulting center distance so the chain runs at the correct tension rather than assuming your original target distance still holds exactly.
What's a reasonable center distance to start from?
A common starting guideline is 30–50 pitches, or roughly the sum of both sprocket pitch diameters, whichever gives a practical, well-tensioned span for your layout.