About this tool
E-Steps & Steps-per-mm Calibration Calculator is a free, in-browser tool for dialling in a 3D printer's motion. It has three modes: correct your extruder E-steps from a measured test extrusion, and compute steps-per-mm for belt-driven axes (X/Y) and leadscrew Z axes for Marlin or Klipper firmware. Nothing is uploaded — all math runs on your device.
For the extruder, mark the filament, command a known length (say 100 mm), measure what actually feeds, and the corrected value is new E-steps = current E-steps × requested ÷ actual. So 93 E-steps that only push 95 mm of a requested 100 mm become 93 × 100 ÷ 95 ≈ 97.9. The tool also shows the extrusion error percentage so you can see how far off you were.
For a belt axis, steps-per-mm = (motor steps/rev × microstepping) ÷ (belt pitch × pulley teeth) — a 200-step motor at 16× on GT2 (2 mm) belt with a 20-tooth pulley gives 80. For a leadscrew, steps-per-mm = (motor steps/rev × microstepping) ÷ screw lead, so an 8 mm lead yields 400. Enter your hardware and copy the values straight into your firmware.
Frequently asked questions
How do I calibrate extruder E-steps?
Mark the filament 120 mm above the extruder, command a 100 mm extrusion, then measure the distance actually consumed. Enter your current E-steps, the requested length and the actual length: new E-steps = current × requested ÷ actual. Flash the new value and repeat until requested and actual match.
What does the extrusion error percentage mean?
It is (actual − requested) ÷ requested × 100. A positive value means the extruder pushed too much (over-extruding) and a negative value means too little; either way, applying the new E-steps brings it toward zero.
How are belt steps-per-mm computed?
steps/mm = (motor full steps per rev × microstepping) ÷ (belt pitch × pulley teeth). The classic combo — 200 steps, 16 microsteps, 2 mm GT2 pitch, 20 teeth — gives 80 steps/mm, the default on most cartesian printers.
How is a leadscrew Z axis different?
A leadscrew converts rotation to linear motion by its lead (mm advanced per turn), so steps/mm = (motor steps per rev × microstepping) ÷ lead. A 200-step motor at 16× on an 8 mm lead gives 400 steps/mm. Everything is calculated locally in your browser.
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