What is the formula used here?

Scaled size = target size / (1 - shrinkage rate). For example, a 100mm target with a 0.5% shrinkage rate needs a scaled size of 100 / 0.995 = 100.50mm.

Where do the default shrinkage percentages come from?

The presets are typical published ranges for common materials (for example PLA around 0.4%, ABS around 0.6%, nylon around 1.5%). Actual shrinkage varies by brand, color, printer settings, and part geometry, so treat presets as a starting point and verify with a test print or your material's datasheet.

Why would Z shrink differently than X and Y?

In FDM printing, the Z axis cools and bonds layer by layer, which can produce a different effective shrinkage than the X/Y plane where a layer is deposited in one continuous pass. Enable the separate Z-axis field if you have measured or been told a different rate for height.

Can shrinkage rate be negative?

Yes. A small number of materials expand slightly instead of shrinking, which would need a downscale rather than an upscale. Enter a negative percentage and the tool will scale the dimension down accordingly.

Does this account for shrinkage in molding or casting, not just 3D printing?

The math is the same for any process where a pattern or model is made oversized to compensate for shrinkage of the final material, including injection molding and casting. Use the shrinkage rate for your specific material and process rather than a 3D printing preset.

Shrinkage Compensation Calculator

Name: Shrinkage Compensation Calculator
Availability: InStock
Author: Nham Vu

Enter the target final size and a material shrinkage rate to get the scaled dimensions to model or slice so the cooled part comes out the right size.

Target Final Dimensions

Length (X)

Width (Y)

Height (Z)

Leave a field blank or 0 to skip that axis.

Material Shrinkage Rate

Material preset

Shrinkage rate (%)

Use a different rate for the Z axis

Enter at least one target dimension and a shrinkage rate

Scaled Print Dimensions

Axis	Target size	Scaled size	Slicer scale

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Summary

Enter the target final size and a material shrinkage rate to get the scaled dimensions to model or slice so the cooled part comes out the right size.

How it works

Enter the target final length, width, and height in millimeters or inches.
Pick a material preset to load a typical shrinkage rate, or enter a custom rate.
Turn on "different Z-axis shrinkage" if your material or process shrinks unevenly along height.
The tool divides each target dimension by (1 minus the shrinkage rate) to get the scaled size.
Read the scaled dimensions and the equivalent slicer scale percentage for each axis.

Use cases

Sizing a 3D print so a snap-fit or press-fit part matches a mating component after cooling.
Working out the slicer scale percentage for a new filament with a known shrinkage rate.
Compensating for SLA/DLP resin cure shrinkage on a dimensionally critical print.
Adjusting a mold or casting pattern for the shrinkage of the final cast material.
Comparing how much scale-up two different materials need for the same target part.

Frequently Asked Questions

Last updated: 2026-07-24 · Reviewed by Nham Vu