3D Print Scale vs Strength Calculator
Calculates how rescaling a 3D model changes its material weight. Use it before re-printing at a different size to predict filament use.
Last updated: September 2026
Formula below · 2 sources (NIST, Wikipedia) · Updated Sep 2026
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About this calculator
When you scale a 3D print uniformly, its volume, and therefore its weight, grows with the cube of the scale ratio: newWeight = (newScale / originalScale)³ × originalWeight. A model scaled to twice its original size uses 8× as much material. This assumes the slicer settings scale with the part; if you keep the same wall (perimeter) count and top/bottom layers, the shells only grow with the square of the scale, so the real weight of a scaled-up part lands somewhat below this cube estimate, and a scaled-down part somewhat above it. Strength does not scale with weight: cross-sectional area, which governs tensile strength, grows with the square of the scale.
How to use
Example: original at 100 %, new scale 150 %, original weight 20 g. 1. Scale ratio = 150 / 100 = 1.5. 2. Cube = 1.5³ = 3.375. 3. newWeight = 3.375 × 20 = 67.5 g. Scaling to 150% increases material use from 20 g to about 67.5 g. Scaling the default 45 g part to 150% gives about 152 g.
Frequently asked questions
Why does doubling the scale of a 3D print use so much more filament?
Because volume scales with the cube of linear dimensions. Double every dimension and you get 2³ = 8 times the volume — and 8 times the material. This surprises many users who expect a roughly 2× increase. Even scaling from 100 % to 120 % produces a 1.2³ ≈ 1.73× volume jump. It is one of the most important factors to check before printing a scaled model, since filament costs can escalate quickly.
How does scaling a 3D print affect its structural strength?
Tensile and bending strength depend primarily on cross-sectional area, which scales with the square of the linear dimension, not the cube. So doubling a print's size gives it 4× the cross-sectional area and significantly more resistance to bending, even though weight increases 8×. However, if you scale down, wall sections can become dangerously thin relative to layer height — sometimes falling below the minimum printable thickness. Always check that walls remain at least 2–3 perimeters wide after scaling down.
When should I change wall thickness instead of just scaling the whole model?
Scaling the entire model changes all dimensions uniformly, which is ideal for decorative or display prints. But for functional parts — brackets, snap-fits, hinges — you often want to keep external dimensions fixed while making walls thicker for strength. In that case, edit the wall count or extrusion width in the slicer rather than scaling the STL. Scaling can also inadvertently push wall thickness below the nozzle diameter, making them impossible to print with a single-pass perimeter.