Model Scaling Calculator
Calculates a model's new dimension after applying a scale factor for 3D printing. Use it when resizing a downloaded model to fit your print bed or match a real-world target size.
About this calculator
Scaling a 3D model multiplies every dimension by a constant factor. The formula is: new_dimension = original_dimension × scale_factor. A scale factor greater than 1 enlarges the model — 1.5× makes it 50% bigger. A factor less than 1 shrinks it — 0.75× reduces it to 75% of the original size. When scaling uniformly (same factor on X, Y, Z), volume scales by the cube of the factor, which dramatically increases filament use: a 2× scale uses 8× the material. Apply different scale factors per axis for non-uniform stretching, but note this distorts proportions. This calculation is especially useful when printing miniatures to tabletop scale, fitting models to a specific print bed size, or creating scaled architectural or engineering mock-ups.
How to use
You download a figurine that is 120 mm tall but need it to fit within 80 mm for your display case. Target scale factor = 80 / 120 = 0.667. For each dimension: if the original width is 45 mm, new width = 45 × 0.667 = 30 mm. If the original depth is 30 mm, new depth = 30 × 0.667 = 20 mm. Enter each original dimension separately with scale factor 0.667 to verify all three axes. The resulting volume will be 0.667³ ≈ 0.296 times the original — meaning the scaled print uses only about 30% of the filament of the full-size version.
Frequently asked questions
How do I calculate the scale factor needed to reach a specific target size?
Divide your desired dimension by the original dimension: scale_factor = target_dimension / original_dimension. For example, to scale a 200 mm wide model down to 150 mm, the factor is 150 / 200 = 0.75. Enter this factor into both your slicer and this calculator to verify the output dimensions before printing. Most slicers accept percentage input rather than a decimal factor, so multiply by 100 — 0.75 becomes 75%. Always double-check all three axes are scaled equally if you want to preserve proportions.
What happens to filament usage when I scale up a 3D model?
Filament volume — and therefore cost and weight — scales with the cube of the linear scale factor. Doubling a model's dimensions (scale factor = 2) increases its volume by 2³ = 8 times, requiring 8× as much filament. Scaling to 1.5× increases material use by 1.5³ = 3.375×. This non-linear relationship surprises many makers who expect a 50% larger model to use 50% more plastic. Always recalculate filament cost after significant scaling using the filament cost calculator, especially before printing large display pieces.
How do I scale a 3D model to a real-world object for a snug fit or replacement part?
Measure the physical target dimensions precisely with digital calipers — aim for 0.1 mm accuracy. Open the model in your slicer, check its current bounding box dimensions, and compute the scale factor as target / current for each axis. If the model and the physical part have the same proportions, a uniform scale works; if not, you need per-axis scaling. Always add a test print of just the critical interface (e.g., a snap joint or screw hole) at full scale before committing to the full part, since FDM printers have tolerances of ±0.1–0.3 mm that may require a small compensating offset.