Stepper Motor Calculator
Built by Johnny Alto · free, no sign-up · updated July 26, 2026
Work out the steps per millimeter to enter in your 3D printer or CNC firmware. Pick your motor's step angle, your driver's microstepping, and whether the axis is driven by a belt and pulley or a leadscrew, and the calculator returns the value your board needs for accurate motion.
Configure0steps per mm
Full step angle0degrees
Lead is the distance the axis travels per full turn of the screw, not the pitch. A common T8 leadscrew with four starts has an 8 mm lead. For belts, steps per mm equals motor steps times microstepping, divided by belt pitch times pulley teeth.
How to calculate stepper steps per mm
Steps per millimeter is the number your printer or CNC firmware uses to turn a commanded distance into the right number of motor steps. It depends on three things: how many full steps your motor takes per revolution, how finely your stepper driver divides each step with microstepping, and how far the axis moves per motor turn through its belt or leadscrew.
For a belt axis, the axis moves the belt pitch times the number of pulley teeth per revolution, so steps per mm equals the motor steps times microstepping, divided by belt pitch times teeth. A classic combination of a 200 step motor at 1/16 microstepping on a 2 mm GT2 belt with a 20 tooth pulley gives exactly 80 steps per mm.
Belt versus leadscrew
A leadscrew axis moves by its lead, the distance traveled per full turn, which is not the same as the thread pitch on a multi-start screw. The common T8 screw has four starts and an 8 mm lead, so a 200 step motor at 1/16 microstepping gives 400 steps per mm, far finer resolution than a belt. Enter the lead, not the pitch, and always confirm by commanding a known move and measuring the actual travel, then fine-tune.
Recommended gear
Bench and build gear
Frequently asked questions
How do I calculate steps per mm?
Multiply your motor's steps per revolution by the microstepping, then divide by the axis travel per motor turn. For a belt that is belt pitch times pulley teeth; for a leadscrew it is the lead.
What is steps per mm for a 20 tooth GT2 pulley?
With a 200 step motor at 1/16 microstepping on a 2 mm GT2 belt and a 20 tooth pulley, it is exactly 80 steps per mm, the most common 3D printer value.
What is the difference between lead and pitch?
Pitch is the distance between adjacent threads; lead is how far the nut travels per full turn. On a multi-start screw the lead is the pitch times the number of starts, so a 4-start T8 with 2 mm pitch has an 8 mm lead.
How do I verify my steps per mm?
Command a known movement, such as 100 mm, measure the actual travel, then scale the value by the ratio of commanded to measured distance and repeat until it matches.
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This calculator gives estimates for planning only; always confirm against your own measurements and species research. Some links are to our buying guides, which contain affiliate links. As an Amazon Associate I earn from qualifying purchases.
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