PLA vs PETG Calculator — Material Comparison

PLA has higher tensile strength (~50 MPa vs ~45 MPa) but is brittle and snaps under impact. PETG is tougher and more impact-resistant, bending before breaking. For structural parts, PETG is generally the better choice due to its ductility.

PLA is not recommended for outdoor use. It degrades under UV exposure, becomes brittle over time, and softens in direct sunlight on warm days (above 55°C surface temperature). PETG or ASA are much better for outdoor applications.

PETG shares its PET base resin with water bottles and food containers, so the base material is food-safe, BPA-free and can be hot-washed. PLA is food-safe in its pure form too, but it softens below dishwasher temperatures (~55°C HDT) and cannot be reliably sterilised, so PETG is the better food-contact choice. Either way, 3D printed parts have layer lines that harbour bacteria — use a food-safe epoxy coating or limit to single-use applications.

PETG has higher melt viscosity and more hygroscopic behaviour, making it stringier. To reduce stringing: dry your filament, increase retraction distance (4-6mm for Bowden), reduce temperature by 5°C, and enable coasting in your slicer.

PLA is significantly easier to print. It has a wider temperature window, lower warping tendency, minimal stringing, and better overhangs. PETG requires more tuning, especially for retraction and bed adhesion (it can stick too well to PEI).