Power Transmission Calculators

These calculators size a complete mechanical drive rather than echo a single textbook formula. The pulley ratio calculator returns the speed ratio i = D₂/D₁, the driven RPM and the rim speed v = π·D·n that both sheaves share without slip, so you can check a reduction before cutting a single bracket. Pair it with the belt length and wrap angle calculator to fix the centre distance, then verify the drive will actually grip: the belt tension calculator applies the capstan equation T₁/T₂ = e^(μθ) to split effective tension into tight- and slack-side strands and warn when low wrap invites slip.

For shaft sizing and motor checks, the torque power RPM calculator solves P = T·ω in either direction, so kW/hp, N·m/lbf·ft and rpm stay consistent before you add efficiency or service factor. The overhung load calculator converts torque, pitch diameter, drive factor, bearing span and load position into radial bearing reactions, load amplification and peak bending moment for shaft sizing; the guide on what overhung load is explains why the nearest bearing can carry more than the applied belt, chain or gear force. For shaft twist, the shaft torsion calculator covers torsional deflection and polar moment. For linear axes, the lead screw torque calculator converts axial load, lead and screw efficiency into required motor torque, then checks available thrust, travel speed, lead angle and critical RPM from screw root diameter and bearing support. The rack and pinion calculator covers the alternate rotary-to-linear layout with travel per revolution and push force from module, teeth, RPM and torque.

For chain drives, the sprocket pitch diameter calculator isolates PD = p/sin(180°/N), chain travel per revolution and chain speed from tooth count and pitch. The roller chain tension calculator then starts from chain pitch, driver sprocket teeth, RPM and transmitted power, returning average chain speed, pitch diameter, effective tension, service-factor design tension and allowable tension margin. The older chain pull calculator remains useful when you already know sprocket pitch diameter. Sprocket and roller-chain length tools work in whole pitches, while the chain length calculator converts teeth, pitch and centre distance into even link counts. The bearing load calculator combines radial and axial load into equivalent dynamic/static catalog loads before the bearing L10 calculator converts C/P into rating life. Every page shows its governing relation and the standard behind it.

It's built for machinists, kart and machine builders, and design engineers who want the real drive parameters — ratio, belt speed, tension, chain pitch, torque, bearing load, thrust and power — not a shallow widget. New to the belt geometry? The guide on how to calculate belt length walks through the derivation.