Tool 09 · Motion
Steppers move in counted clicks, and every firmware asks the same question: how many clicks per millimetre? This tool computes steps/mm for belts, leadscrews and wheels — and warns you when your target speed is a fantasy for an open-loop motor.
GT2 = 2 mm per tooth
Please enter positive values in every field.
Motion spec
mm per rev — belt: pitch × teeth · screw: lead · wheel: π × diameter
Steps per mm = (steps/rev × microstepping) ÷ mm per rev
Motor RPM = speed × 60 ÷ mm per rev
Step frequency = steps per mm × speed
The two numbers to watch on the nameplate are the last two. Motor RPM tells you whether the motor can do it: stepper torque collapses with speed, and a hobby NEMA 17 at 12–24 V is honest up to roughly 300–600 RPM. Step frequency tells you whether the controller can do it: an Arduino running AccelStepper tops out around 4,000 steps/s, 32-bit boards manage 100k+, and dedicated drivers with hardware pulse generators go further still.
Note what microstepping does and doesn't buy: 1/16 microstepping makes motion sixteen times smoother and quieter, but the usable positioning accuracy under load remains close to the full-step figure shown above — the incremental holding torque between adjacent microsteps is only a few percent of rated torque.
Choosing between a stepper and a geared DC motor for a drivetrain? The Motor Sizing Calculator gives the torque requirement either way, and if you go DC, the Odometry Calculator replaces counted steps with counted encoder ticks.
Convergent evolution: 1.8° motor × 16 microsteps = 3200 steps/rev, on a 20-tooth GT2 pulley moving 40 mm/rev, is 80. Change any factor and the firmware constant changes with it — which is exactly what this tool recalculates.
Only the faceplate size (1.7 vs 2.3 inches), not the torque. Motor length within a size family is what varies torque; a long NEMA 17 out-pulls a short NEMA 23. Read the holding torque spec, not the frame number.
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