KEVOS® MAKEOS · Power Transmission
Roller Chain Length and Centre Distance
How many links does this roller chain drive need, and what centre distance results?
Chain length in pitches for two sprockets at a centre distance, rounded to an even number of links, the exact centre distance for that length, and chain speed.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Chain pitch | mm | Chain pitch (e.g. 15.875 mm for 10B or 50/ANSI). |
| Small sprocket teeth | teeth | Teeth on the small sprocket. |
| Large sprocket teeth | teeth | Teeth on the large sprocket. |
| Approximate centre distance | mm | Wanted centre distance (often 30–50 pitches). |
| Small sprocket speed | rpm | Speed of the small sprocket. |
Method and formulas
- L (pitches) = 2C/p + (z₁ + z₂)/2 + ((z₂ − z₁)/2π)² ÷ (C/p).
- Round up to an even number of links (avoids an offset link).
- C = (p/4)[L − (z₁ + z₂)/2 + √((L − (z₁ + z₂)/2)² − 8((z₂ − z₁)/2π)²)].
- Example: 17/51 teeth at about 600 mm need 112 links, giving an exact centre distance of 613.11 mm.
Limitations
- Allow adjustment for chain wear and sag; the exact centre distance is for a new, tight chain.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Order the right chain length
- Set the centre distance for a standard chain
- Check chain speed
Who it is for
- Design engineers
- Maintenance engineers
- Automation engineers
What you get
- Chain length in pitches (exact and rounded to even)
- Chain length in mm
- Exact centre distance for the rounded chain
- Chain speed and wrap on the small sprocket
Interpreting the result
- Keep at least about 120° of wrap on the small sprocket.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2537–2560. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
