Base pitch is the arc length between the starting points of the involute curves of adjacent teeth on the base circle. For involute gears on parallel axes, the base pitches of mating gears must be equal for proper meshing. This tool helps you find or verify base pitch for reverse engineering and inspection. Use either a vernier caliper or a flange micrometer when measuring gear teeth spans.
Base pitch finder tool to help narrow down the number of teeth to span (k) by pressure angle to then verify the base pitch.
Enter a tooth count to compute the recommended span range. The span inputs stay visible so you can keep the page layout stable while editing.