Steps per mm Calculator
Calculate corrected axis steps per millimeter from commanded and measured movement.
Movement test
The axis's current M92 value.
The move you commanded the axis to make.
What you measured with calipers.
Calibrated steps/mm
81.63 steps/mm
- Current steps/mm
- 80 steps/mm
- Adjustment
- +2.04%
How it's calculated
Command an axis to move a known distance, measure how far it actually moved, and scale your current steps/mm by the ratio between them:
Correction factor
Commanded distance ÷ Actual distance
Adjustment percentage
((New steps/mm − Current steps/mm) ÷ Current steps/mm) × 100
New steps/mm
Current steps/mm × Correction factor
This uses the same ratio direction as E-steps calibration (it's the same underlying concept applied to a motion axis instead of the extruder). It corrects the mathematical relationship between commanded and actual movement — it isn't automatically the right fix for every dimensional accuracy problem, since belt tension, mechanical issues, and other factors can cause the same symptom.
Assumptions
- Your inputCurrent steps/mm, commanded distance, and actual measured distance — you enter these directly, from your own printer and a caliper measurement.
- Derived valueCalibrated steps/mm and the correction factor are derived exactly from those inputs — no approximation in the math itself.
Worked example
Current steps/mm is 80. You command the axis to move 100mm and measure that it actually moved 98mm.
New steps/mm = 80 × 100 ÷ 98 ≈ 81.63 steps/mm.
Adjustment = ((81.63 − 80) ÷ 80) × 100 ≈ +2.04%.
Frequently asked questions
What does steps per mm mean?
Steps per millimeter tells the firmware how many motor steps correspond to 1mm of movement on an axis. It depends on your motor's step angle, microstepping setting, and the mechanical setup (belt pitch and pulley tooth count, or leadscrew pitch). If it's inaccurate, the firmware will consistently move slightly more or less than commanded, causing dimensionally inaccurate prints.
How do I calculate corrected steps/mm?
Command the axis to move a known distance (e.g. 100mm), then physically measure how far it actually moved with calipers. Enter your current steps/mm along with the commanded and measured distances — the calculator applies the standard correction formula.
Should I change X/Y steps per mm to fix dimensional accuracy?
Only if you've confirmed the axis itself is moving the wrong distance — for example by directly measuring gantry travel with calipers over a known commanded move. Many dimensional accuracy problems people blame on steps/mm are actually caused by something else (see below), and changing steps/mm to compensate for a different problem can mask the real issue and cause new ones.
Is steps/mm the same as E-steps?
E-steps is just the extruder's version of steps/mm — the same underlying concept (motor steps per millimeter of movement) applied specifically to filament extrusion rather than X/Y/Z motion. This calculator works for any axis; for extrusion specifically, the E-Steps Calculator uses the same math with extrusion-specific labels.
Why is my printed part still the wrong size after calibration?
Dimensional accuracy depends on more than motion calibration. Common culprits include belt tension, mechanical play or backlash, extrusion width/flow calibration, material shrinkage (especially with ABS/ASA), the slicer's horizontal expansion setting, and even inaccurate source model dimensions. If a part is off by a consistent small percentage across many prints, motion calibration is worth checking — but if it's inconsistent or specific to certain features, look elsewhere first.
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