Chain & Sprocket Calculator

Pick the chain, set the sprocket teeth and the distance between shafts. Get the number of links, the exact center distance for an even chain, sprocket sizes, chain speed and load.

Standard

Chain

Driver teeth

Driven teeth

Driver speed

RPM

Power

Power is optional. It gives torque, chain pull and the safety factor.

I know the

Center distance

Best between 30 and 50 chain pitches.

Drag a sprocket to move it, rim dot for teeth

Sprockets

Dimension	Driver	Driven

Sprocket finder

Enter the output speed you need. Pairs are sorted by speed error, then by size.

Target driven speed

RPM

Driver sprocket

Driver	Driven	Ratio	Speed	Error

Multiple Chain Drives – RPM Reduction

Chain several sprocket pairs on shared shafts. The driven sprocket of each drive sits on the same shaft as the driver of the next. Uses the chain picked above and starts from the driver speed.

Number of drives

How it is calculated

p is the chain pitch, z₁ and z₂ the sprocket teeth, C the center distance. The link count uses the standard chain length formula; the center distance for a whole number of links is solved from the same formula, so the two always agree.

Chain length Lp = 2·C/p + (z₁ + z₂)/2 + ((z₂ − z₁)/(2π))² · p/C (links) Center distance C = p/4 · [ B + √(B² − 8·((z₂ − z₁)/(2π))²) ], B = Lp − (z₁ + z₂)/2 Pitch diameter Dp = p / sin(180°/z) Outside diameter Do ≈ p · (0.6 + cot(180°/z)) Speed ratio i = z₂ / z₁, n₂ = n₁ · z₁ / z₂ Chain speed v = z₁ · p · n₁ / 60 000 (m/s, p in mm) Chain pull F = 1000 · P / v (N, P in kW) Speed variation Δv = (1 − cos(180°/z)) · 100 % (chordal action)

Rules of thumb used for the warnings: at least 17 teeth on the small sprocket for smooth running (9 is the absolute minimum), no more than about 120 teeth on the large one, center distance 30–50 pitches and no more than 80, and at least 120° of wrap on the small sprocket. Breaking loads are the ISO 606 minimum tensile strengths for simplex chain; a static safety factor of 7 or more is a common starting point. Always check the chain maker's power rating tables for the final choice.