V-Belt Length & Center Distance CalculatorV-BELT CENTER DISTANCE

1. 1Choose the belt section (A–E).
2. 2Enter the driver and driven pitch diameters dp1 and dp2.
3. 3Enter the desired centre distance and, optionally, the motor speed.
4. 4Read the recommended belt (e.g. A45), actual centre distance and error, and check the wrap-angle and speed verdicts.

V-belts are endless and cannot be cut to length. Start from the desired centre distance C and both pitch diameters, compute the required pitch length with the exact open-belt formula, pick the nearest standard belt (e.g. A45) and solve the actual centre distance back from its pitch length. The difference ΔC must be absorbed by motor slots or a tensioner — typically allow +3% for take-up and −1.5% for installation.

Sections A to E grow in size, from a top width of about 12.5 mm (A) to 38 mm (E), and in power capacity. The small sheave should have at least 120° of wrap and belt speed should stay below 30 m/s; large diameter differences at short centres reduce the wrap. The tool also checks minimum pitch diameters (A71, B112, C180, D315, E500 mm). Custom sheaves or guards can be generated here and made by Orinovate.

L = 2√(C² − e²) + π(dp1 + dp2)/2 + 2e·asin(e/C), e = (dp2 − dp1)/2
Li = belt number × 25.4 mm
Lp = Li + 33 (A) / 46 (B) / 74 (C) / 84 (D) / 114 (E)
C_actual solved numerically from L(C) = Lp, ΔC = C_actual − C
θ1 = 180° − 2·asin(e/C)
v = π · dp1 · n1 / 60000 (m/s)

Results are for design reference only; confirm against supplier catalogues and the applicable standards before manufacturing.