How to use the steps per mm calculator
- Choose the drive type: a belt and pulley (3D printer and plotter X/Y axes) or a lead screw / threaded rod (Z axes, CNC routers, linear stages).
- For a belt, pick the belt type (GT2 = 2 mm pitch) and enter the number of pulley teeth. For a screw, pick a preset or enter the lead — the distance the nut moves in one full turn.
- Select the motor step angle (1.8° = 200 steps/rev for most NEMA 17 motors) and the driver's microstepping.
- Read steps per mm, the resolution of one microstep and the top speed for your controller's step frequency. Copy the Marlin, GRBL or Klipper setting from the code box.
Tap any row of the common-setups table to load it.
Formula
full steps/rev = 360° ÷ step angle (1.8° → 200)
steps/rev = full steps/rev × microstepping
travel/rev (mm) = pulley teeth × belt pitch (belt)
= lead = thread pitch × number of starts (screw)
steps/mm = steps/rev ÷ travel/rev
resolution (µm) = 1000 ÷ steps/mm
max feed (mm/s) = step frequency (Hz) ÷ steps/mm
Common setups (1.8° motor, 1/16 microstepping)
| Setup | Travel per rev | Steps/mm | Resolution per microstep | Steps/mm with a 0.9° motor |
|---|---|---|---|---|
| GT2 belt, 20-tooth pulley | 40 mm | 80 | 12.5 µm | 160 |
| GT2 belt, 16-tooth pulley | 32 mm | 100 | 10 µm | 200 |
| T8 lead screw, 8 mm lead (Tr8×8) | 8 mm | 400 | 2.5 µm | 800 |
| T8 lead screw, 2 mm lead (Tr8×2) | 2 mm | 1600 | 0.625 µm | 3200 |
| M8 threaded rod, 1.25 mm pitch | 1.25 mm | 2560 | 0.39 µm | 5120 |
| M5 threaded rod, 0.8 mm pitch | 0.8 mm | 4000 | 0.25 µm | 8000 |
That is why so many printers, including the Creality Ender-3, use 80 steps/mm on X and Y and 400 steps/mm on Z.
Microstepping and drivers
| Driver | Highest microstepping | Default with no jumpers |
|---|---|---|
| A4988 | 1/16 | full step |
| DRV8825 | 1/32 | full step |
| TMC2208 / TMC2209 | up to 1/256 | set by MS1/MS2 pins or UART |
Common mistakes
- Mixing up pitch and lead. A Tr8×8 screw has a 2 mm thread pitch but 4 starts, so it moves 8 mm per turn. Using 2 mm instead of 8 mm makes the axis move four times too far.
- Forgetting the microstep jumpers. An A4988 or DRV8825 with nothing on MS1–MS3 runs in full-step mode, so a setting of 80 steps/mm moves the axis 16 times too far.
- Counting the belt teeth instead of the pulley teeth. Only the pulley's tooth count matters.
- Asking for too much speed. Torque falls as RPM rises; if the motor skips steps, lower the speed or acceleration before blaming the steps/mm value.
- Calculating extruder steps. Extruder gears vary, so measure and calibrate E-steps by pushing 100 mm of filament instead.
New to stepper motors? Read understanding stepper motors: drive modes and control. For wheeled robots, use the wheel RPM and speed calculator and the gear ratio calculator. Want to build your own machine with guidance? Join a Thinking Robot workshop or browse our kits.
