Gear Center-to-Center

Find the center distance for a spur gear pair given diametral pitch and tooth counts.

C = (N₁ + N₂) / (2 · DP)

Diametral pitch (DP)

Pinion teeth (N₁)

Gear teeth (N₂)

2.1000 in / 53.34 mm

Notes

Assumes standard 20° pressure angle, no profile shift.
For helical gears, use normal DP and divide the result by cos(helix angle).
Result is shown in both inches and millimeters since DP is an imperial pitch but designs often use metric mounting features.