Wall thickness calculator
Wall thickness decides whether a part survives being held — not infill, which is what most people reach for. Set the nozzle, the perimeters and what the part is for, and it tells you whether that is enough.
The rule behind it
A wall should be a multiple of the extrusion width. With a 0.4 mm nozzle the right walls are 0.8, 1.2, 1.6 mm. A 1 mm wall is not better than 0.8: the slicer lays two passes and is left with a 0.2 mm gap it fills badly.
Under bending, the surface material carries almost all the load. That is why 4 perimeters with 15% infill hold better than 2 perimeters with 50% — using less plastic.
What else matters
- Orientation on the bed: prints break between layers, not within them.
- Threads and snap fits need at least 2 mm of material around them.
- Below 0.8 mm nothing is safe: if the slicer rounds down, the wall disappears from the print.
How many perimeters?
Three for ordinary parts, four or five for loaded ones. Above six the gain is small next to the added time.
How much infill?
15–20% covers most parts once the walls are thick enough.
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