Homeâ€ēCalibrationâ€ēSkew Correction
Step 8 of 9

Skew Correction

Make sure your printer moves in true 90° in all axes. Fix X/Y, X/Z and Y/Z skew for perfectly square prints.

⏱
Time
20–40 min
📊
Difficulty
Intermediate
⚡
Impact
High
BEFORE (SKEWED)
Not 90°
87°93°A: 141.6mmB: 143.1mm100.0mm
MEASURE
& VERIFY
Check all
sides and
diagonals
AFTER (CORRECTED)
True 90°
90°90°90°90°A: 141.4mmB: 141.4mm100.0mm
ℹī¸
Why this matters: Your printer may be dimensionally accurate and still not be square. Skew affects: assemblies, functional parts, mechanical fits and large prints.
1
How to Correct Skew
1
Print calibration model
Use a square / cube calibration model with accurate dimensions. 100×100mm minimum.
2
Measure X and Y
Use calipers to measure both sides and compare to the expected size.
3
Measure diagonals
Measure both diagonals (A and B) across the square. They must be equal for true 90°.
4
Compare values
Diagonals should be equal. Sides should match expected size. Any difference = skew.
5
Calculate skew correction
Enter your measurements in the calculator below to get correction values.
6
Apply correction
Set the values in your firmware using SET_SKEW (Klipper) or M852 (Marlin).
7
Re-test
Print again and verify. Repeat if needed. Small corrections may need multiple iterations.
2
Skew Calculator (XY Plane)
AB
Measure A and B corner-to-corner. They should be equal for true 90°.
ℹī¸ Measure carefully. Small errors can cause over-correction.
3
Your Results
Enter all measurements and click Analyse.
ℹī¸ Key distinction
Equal diagonals = square part. But square ≠ correct size.
A part can be perfectly square and still be 2% too small.
That is shrinkage — not skew.
← Back to Retraction
Next: Shrinkage Compensation →
📋Calibration Order
⊗Common Mistakes
⊗Trying to fix skew using Flow Rate / EM
⊗Trying to fix skew using X/Y scaling
⊗Ignoring frame alignment first
⊗Not measuring diagonals — sides alone are not enough
⊗Using a warped or poorly printed test part
⭐Pro Tip
Always fix the mechanics first. Software skew correction should be the final adjustment, not the first solution.
🔲 Square frame
🔩 Tight belts
🗜ī¸ Rigid mounts
📐 Level bed
→Next Step
Shrinkage Compensation
Compensate for material shrinkage and make your parts dimensionally accurate.
Go to Shrinkage Compensation →
❓Need Help?
Parts still not square after correction?
Troubleshooting →