Calculating Roller Chain Length
Given two sprockets, a known distance apart. The number of teeth on each sprocket is known. The pitch of the chain is also known. This page calculates the length of the chain required to wrap both sprockets, and the number of links of chain to do so. The distance between sprockets can be adjusted to make an integer number of links. Better still, make the number of links an even integer so that an offset link is not required. This program does not take into account chain stretch or wear of chain or sprockets, or link tolerances.
The accuracy of this model is limited by the fact that links do not bend as they wrap around a sprocket. The new formula corrects this issue.
Note: If there is a large size difference between the two sprockets, you may want to avoid minimum spacing between them as this will decrease the wrap length around the smaller sprocket, increasing the tendancy of the chain to jump teeth or slip.