Steps per mm calculator
Work out the steps/mm (or steps per degree) for your CNC or 3D-printer axis, leadscrew, belt or rack & pinion, and copy a ready-made GRBL or Marlin config line.
Motor step angle
Microstepping
1:1 direct drive → 1× steps
Transmission
Advanced settings
Steps / mm
400.000steps/mm
(200 × 16 × 1) ÷ 8 mm = 400.000 steps/mm
3200 steps / motor rev8 mm / rev1:1 direct drive
Resolution / microstep
0.00250 mm · 2.500 µm
Max feedrate
4500.0 mm/min
GRBL
$100=400.000Marlin
#define DEFAULT_AXIS_STEPS_PER_UNIT { 400.000, …, …, … }or set live: M92 X400.000
Common steps/mm values
Everyday setups, all with a 1.8° motor (200 steps/rev) at 16× microstepping (3200 steps per motor turn), 1:1 drive.
| Setup | Transmission | steps/mm |
|---|---|---|
| T8 4-start | Leadscrew, lead 8 mm | 400 |
| T8 2-start | Leadscrew, lead 4 mm | 800 |
| T8 1-start | Leadscrew, lead 2 mm | 1600 |
| SFU1605 | Ball screw, lead 5 mm | 640 |
| SFU1610 | Ball screw, lead 10 mm | 320 |
| SFU1204 | Ball screw, lead 4 mm | 800 |
| GT2 16T | Belt, 32 mm/rev | 100 |
| GT2 20T | Belt, 40 mm/rev | 80 |
| M8 rod | Leadscrew, lead 1.25 mm | 2560 |
Frequently asked questions
What is steps per mm?
Steps per mm is how many motor steps, including microstepping and any gearing, move an axis one millimetre. Firmware such as GRBL and Marlin needs this number to turn requested moves into step pulses.
How do I calculate steps per mm?
steps/mm = (motor steps per revolution × microstepping × gear ratio) ÷ travel per revolution. Travel per revolution is the leadscrew lead, or pulley teeth × belt pitch, or pinion teeth × module × π.
Why is a T8 leadscrew 400 steps/mm?
A T8 4-start screw has an 8 mm lead. With a 1.8° motor (200 steps per rev) at 16× microstepping that is 3200 steps per turn ÷ 8 mm = 400 steps/mm.
What is the difference between lead and pitch?
Pitch is the distance between adjacent thread crests; lead is how far the nut travels in one full turn. On a 4-start screw the lead is four times the pitch, entering pitch by mistake gives four times too many steps/mm.
Where do I put the value in GRBL or Marlin?
In GRBL set $100/$101/$102 for X/Y/Z. In Marlin edit DEFAULT_AXIS_STEPS_PER_UNIT, or send M92 for a live change. The calculator generates both lines for your chosen axis.
How do I verify my steps per mm?
Command a known move such as 100 mm, measure the actual travel, then multiply your steps/mm by commanded ÷ measured. Repeat until the move is accurate.
steps/mm = (motor steps/rev × microstepping × gear ratio) ÷ travel per revolution. Always confirm calibration by commanding a known move and measuring it.