Belt length and pulley centers
Solve open-belt pitch length or center distance for two pulleys, with wrap angles. Drag the graph handles to change inputs and explore the result.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
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How it works
- = / 2; = / 2
- Δr = − ; = 2√(C² − Δr²) + π( + ) + 2Δr × asin(Δr/)
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Enter pitch diameters and pitch length in the same unit. Uses exact tangent geometry for an uncrossed belt; the center-distance mode solves it numerically. Belt thickness, tension, stretch and tooth compatibility are excluded. Example: two 100 mm pitch pulleys, 200 mm apart, need a 714.159 mm pitch length.
Sources
- York Industries — center distance and belt length Sources reviewed: 2026-10-22
