Material Shrinkage Scale Factor Calculator

All plastics shrink as they cool from the melt temperature to room temperature. For most FDM materials the shrinkage is small (0.2-0.5%) and within acceptable tolerances for general parts. For engineering applications and precision fits, it matters.

ABS and ASA shrink the most of the common FDM materials — 0.5-0.8% linearly. This means a 100 mm ABS part comes out 99.2-99.5 mm without compensation. Over a 200 mm part, that is a 1-1.6 mm shortfall. Nylon can shrink 1-2% and has the additional problem of moisture-induced dimensional change after printing.

Typical shrinkage rates (linear, room-temperature measurement):

• PLA: 0.2-0.3%
• PETG: 0.2-0.4%
• ABS: 0.5-0.8%
• ASA: 0.4-0.7%
• Nylon PA6: 0.8-1.5%
• Nylon PA12: 0.5-1.0%
• PC: 0.5-0.8%
• TPU: 0.5-1.0%

Scale factor formula:

scale (%) = 100 / (1 - shrinkage%) or equivalently: scaled_dimension = target / (1 - shrinkage%)

For 0.7% ABS shrinkage: scale = 100 / 0.993 = 100.705%. A 100 mm target should be modeled at 100.7 mm.

Important caveat. Shrinkage in FDM is not perfectly isotropic. X and Y directions (within the print plane) typically shrink more than Z (layer stacking direction). If precision is critical in all three axes, measure and compensate each axis separately.