V-Belt Length Calculator

Inputs

View results
Use the same two-sheave geometry in either direction.
Use pitch / datum diameter, not outside diameter.
mm
Use pitch / datum diameter, not outside diameter.
mm
Distance between sheave centers.
mm
Optional: set to 0 if speed is not needed.
rpm

Results

Default result
Edit inputs
Belt pitch length(L)
1,363.8mm
Pass

calculated pitch length

Also computed

Center distance(C)Pass400mm

known center distance

Small-sheave wrap(θₛ)Pass158.4°

comfortable wrap for a friction belt

Speed ratio(i)2.5

reduction

Driven speed(n₂)700rpm

Belt speed(v)9.163m/s

Method notes 3 notes
  • Use pitch / datum sheave diameters. A V-belt rides below the outside rim, so OD usually gives a belt that is too long.
  • Open-drive length: L = 2C + (π/2)(D₁ + D₂) + (D₂ − D₁)²/(4C). Center distance is solved by the positive quadratic root.
  • Small-sheave wrap limits grip. If it drops below about 120°, reduce the ratio, increase center distance or add an idler.

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