Material Shrinkage Compensation Calculator | PrintCalcLab

Calculate print dimensions to compensate for PLA, ABS, PETG shrinkage.

Thermoplastics contract as they cool from extrusion temperature to room temperature, so a part sliced at exactly 100 mm comes off the bed slightly smaller. For press fits, bearing seats, and threaded inserts, that difference is the gap between a working part and a reprint. This calculator scales your target dimension up before printing using per-material shrinkage rates, with separate values for the XY plane and the Z axis, which shrink differently because layers cool under different constraints.

How It Works

The compensated print dimension is target ÷ (1 − shrinkage rate ÷ 100) — a division rather than a simple percentage addition, because shrinkage acts on the printed size, not on the target. Rates come from a per-material table: PLA and PETG at 0.3% XY / 0.2% Z, TPU at 0.4/0.3, HIPS at 0.5/0.4, PC at 0.6/0.5, ABS and ASA at 0.7/0.5, and Nylon at a substantial 1.5% XY / 1.0% Z. A 100 mm ABS dimension in XY therefore becomes 100.70 mm to print, while the same dimension in Nylon becomes 101.52 mm.

FAQ

Why divide instead of just adding the percentage?

Because shrinkage applies to the printed dimension: print 100.70 mm of ABS, let it lose 0.7% of itself, and you land on the 100 mm target. Simply adding 0.7% of the target would leave the part fractionally undersized — negligible at 0.3%, but real at Nylon's 1.5%.

Why is Nylon so much worse than PLA?

The table rates Nylon at 1.5% in XY — five times PLA's 0.3% — reflecting its semi-crystalline structure, which contracts substantially as crystals form during cooling. That is also why Nylon benefits from an enclosure and a stable ambient temperature.

Why are XY and Z shrinkage rates different?

Each layer is reheated and constrained by the layers below as it bonds, so the vertical direction relaxes differently from the free in-plane directions. The table reflects this with lower Z rates, such as ABS's 0.5% vertical versus 0.7% in-plane.

Are these rates exact for my printer?

They are representative values; actual shrinkage moves with print temperature, cooling, infill, part geometry, and even filament brand. For critical fits, print a calibration object, measure it, and adjust — the calculator gets you into the right neighborhood on the first try.