3D Model Scaling Calculator

Scaling every dimension by a factor s multiplies the volume — and so the material and weight — by s³. Double a model (s = 2) and it uses about eight times the filament and takes several times longer, not twice. Print time lands somewhere between s² and s³ depending on whether the part grew taller (more layers) or wider (more perimeter).

Use the target-size mode. Enter the current dimension and the length you want that axis to become; the calculator divides desired ÷ current to get the scale factor, then applies it to all three axes so the model stays proportional.

Printed size is inversely proportional to the ratio number, so the scale factor is 72 ÷ 100 = 0.72 — the 1:100 model is 72% of the 1:72 one. A 32 mm 1:72 figure becomes about 23 mm at 1:100. The ratio mode does this and warns if you are shrinking so far that fine detail will clog.

Divide by (1 − shrinkage), not add the percentage. For a material that shrinks 3%, scale the model to 1 ÷ (1 − 0.03) = 1.0309, roughly 103.1%, not 103%. Typical linear shrinkage: PLA ~0.2–0.5%, ABS ~0.5–0.7%, nylon up to 1.5%, most resins under 1%. The shrink mode presets common materials.

Practically, yes. Features thinner than about one to two nozzle widths (0.4 mm printer: sub-0.8 mm details) stop printing, and text under ~6 mm tall becomes unreadable. Below a 0.2× scale factor the calculator flags that walls may vanish — thicken features rather than only scaling.

For a plain proportional resize, the slicer is fine and instant. Scale in CAD when you need non-uniform resizing, wall thickness kept constant while the part grows, or features re-added after a big downscale — slicer scaling shrinks walls too, which is usually not what you want for functional parts.