When should you use this tool?
Use it when an STL/3MF model must reach a target dimension, model scale or printer build volume, including a fit check and uniform scaling.
Tool · Scaling & Build Volume
3D Scale & Fit Calculator
Scale models to a target size, convert percentages and model scales, calculate new X/Y/Z dimensions and find the largest uniform size that fits your build volume.
Unit
Use the same unit for all dimensions within a mode.
Original size → target size
Ideal when a part, helmet or figure must reach a specific dimension.
Scale125,00 %
Factor1,250×
Volume factor1,953×
New size125 × 100 × 150 mm
Scale by percentage or factor
Calculate the new bounding box. Optionally scale X, Y and Z independently.
New X size125 mm
New Y size100 mm
New Z size150 mm
Volume factor1,953×
Convert model scale 1:x
For figures, miniatures, dioramas and scale models, e.g. 1:6 to 1:10 or 1:12 to 1:8.
Scale60,00 %
Factor0,600×
Volume factor0,216×
New size108 × 54 × 180 mm
Fit model to build volume
Calculates the maximum uniform scale and automatically checks all six X/Y/Z orientations of the bounding box. Optional reserved space can account for a brim, prime tower or known exclusion zones.
Model
Build volume
Reserve additional build space optional
Max. scale—
Best orientation—
Limiting axis—
Free clearance—
New size—
Volume factor—
What the calculator also considers
Uniform scaling changes X, Y and Z by the same factor. Geometric volume scales with the cube of that factor: 150% means 3.375× theoretical volume. Real FDM filament use does not follow this exactly because walls, infill, top/bottom layers and supports do not scale in a purely volumetric way.
Build-volume fit is a bounding-box check
The fit mode tests orthogonal X/Y/Z axis permutations. Optional X/Y/Z reserves can roughly subtract known space requirements. It still does not replace a slicer check for diagonally tilted models, dynamic toolhead clearance or complex exclusion zones.
Use non-uniform scaling carefully
Different X/Y/Z percentages can be useful for costumes, molds or targeted tolerance corrections, but they also change proportions, hole geometry, wall thicknesses and mechanical fits.
For technical fits: Check flow, first-layer geometry and material shrinkage first. A global scale factor is not always the right correction for one undersized hole or for elephant foot.
Fit problem rather than scaling?
If CAD dimensions are correct but the print is systematically smaller/larger or holes do not fit, use the Dimensional Accuracy & Shrinkage Calculator instead of blindly scaling the whole model.
Tool guide
3D Scale & Fit Calculator: when and how should you use it?
A useful result starts with the right question. These notes explain what the tool is designed for, how to interpret its output and where a calculation is intentionally only an approximation.
How to use it well
Enter original dimensions or bounding box and choose target size, percentage/factor, scale ratio or build-volume mode. For mating parts, then account for real print tolerance and required clearance.
Limits & important notes
Scaling does not automatically preserve functional tolerances. Holes, snap fits, wall thicknesses and threads can become unsuitable after large scale changes.
Frequently asked questions
What is the difference between percentage and scale factor?
100% equals factor 1.0, 50% equals 0.5 and 200% equals 2.0. They describe the same uniform scale in different notation.
Can I scale a model exactly to the maximum build volume?
Geometrically yes, but practical clearance may be needed for brim, plate edges and machine margins. The fit mode therefore includes a safety margin.
Why can a scaled part stop fitting its mate?
Clearances scale too. A designed 0.2 mm gap becomes only 0.1 mm at 50%, while printer error and material shrinkage do not scale in the same simple way.
Should I scale X, Y and Z independently?
Only deliberately. Non-uniform scaling changes proportions, angles and often fits. Uniform scaling is usually safer for a pure size change.
These tools provide guidance and calculations from your inputs. Safety-critical, electrical or highly loaded parts require additional verification.
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