Machine design tool · V0.8

Belt & Pulley Speed Calculator

Use a no-slip first-pass relationship to explore pulley sizes and driven speed, plus an approximate open-belt length.

Driver pitch diameter D₁ (mm)

Driven pitch diameter D₂ (mm)

Driver speed n₁ (rpm)

Center distance C (mm)

Driven speed—

Speed ratio—

Belt speed—

Approx. open-belt length—

n₁D₁ ≈ n₂D₂ · L ≈ 2C + π(D₁+D₂)/2 + (D₂−D₁)²/(4C)

No-slip, pitch-diameter approximation for an open belt. Real belt selection must use manufacturer pitch data, wrap angle, tension, power rating, service factor, installation take-up and allowable speed.