3D Printing Calculators
Thermal Shrinkage Scaling Calculator
https://www.3dsizing.com/calculators/thermal-shrinkage/
Estimate only — not firmware, a slicer profile or a shop quote. Confirm on a test print.
Thermal Shrinkage Scaling Calculator
Plastic shrinks as it cools. If a 100 mm ABS boss comes out 99.2 mm, you scale the mesh up before slicing. This uses a linear shrinkage fraction per material, or your own percent.
Inputs
Results
- Shrinkage used
- 0.200%
- Slicer scale
- 100.200%
- Expected CAD size after scale
- 100.200mm
Type this in the slicer uniform scale field (e.g. 100.8%).
Calculation method
Linear shrinkage is a fraction: PLA 0.002, PETG 0.003, ABS 0.008, ASA 0.007, nylon 0.012, PC 0.006. Custom mode uses the percent field divided by 100. The mesh must be larger than the cold part, so scale factor = 1 / (1 − shrinkage). Slicer scale percent is that factor times 100. Scaled size is nominal millimetres times the factor. Invalid if shrinkage is 100% or more (division by zero) or the model size is not positive.
Exact formula
If material is custom, shrinkage = custom_% / 100; otherwise shrinkage is the option value (e.g. ABS 0.008). scale = 1 / (1 − shrinkage). scaled_mm = model_mm × scale. Limits: Uniform isotropic scale; XY vs Z and holes differ. Table fractions are planning defaults, not a measured cube.
Measure your own percent
custom% = (CAD − measured) / CAD × 100. Average X and Y on a 50 mm cube after the part is cold.
Frequently asked questions
Uniform scale or per-axis?
This page is uniform. Z often shrinks differently. For holes, also look at print-in-place clearance rather than only scaling the whole STL.
Why scale up, not down?
The printed part is smaller than CAD after cooling. You enlarge CAD so the cold part lands on the drawing.
Will an enclosure change this?
Yes. A warm chamber reduces ABS warp and can cut the effective shrink. Re-measure in the environment you produce in.
Holes came out tighter than the cube.
Holes shrink inward on top of polymer shrink. Combine this scale with XY compensation or the clearance tool.
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