PLA vs PETG vs ABS: Which Filament to Use

PLA, PETG and ABS cover the overwhelming majority of consumer FDM printing, and the choice between them is usually made for the wrong reason: which one sounds strongest. Strength is rarely the deciding property. Print temperature, warping behaviour, whether the machine is enclosed, and the temperature the finished part will live at decide it far more often.

Everything below is drawn from published vendor documentation, not from bench work of any kind. Where a number appears, its source is named so the original can be checked.

The three materials at a glance

Property	PLA	PETG	ABS
Nozzle temperature	215 °C first layer, 210 °C after	230 °C first layer, 240 °C after	255 °C
Bed temperature	60 °C	85 °C first layer, 90 °C after	100 °C, 80–110 °C by part size
Enclosure	Not required	Not required	Required
Warping	Not prone to significant warping	Does not shrink or warp	Significant warping
Heat resistance of the part	Softens above about 60 °C	Suitable below about 80 °C	Good high-temperature resistance
UV resistance	Degrades under UV	Suitable for most exterior use	Lacks UV resistance, yellows outdoors
Fumes	Low concern	Low concern	Potentially dangerous (styrene), ventilation required
Build surface note	Satin or smooth PEI	Powder-coated textured or satin; smooth PEI can be damaged	Smooth or powder-coated PEI with glue stick
Published density, by brand	1.24 (Prusament PLA), 1.17 (PolyLite PLA)	1.27 (Prusament PETG), 1.25 (PolyLite PETG)	1.12 (PolyLite ABS data sheet)
Forced-air drying	50 °C for 8 h	60–65 °C for 8 h	75–85 °C for 8 h
Difficulty	Easiest	Easy	Hardest of the three

Print temperatures, bed temperatures, surface recommendations, warping and UV behaviour come from the Prusa Knowledge Base pages for each material. Drying figures are the forced-air convection oven column of Bambu Lab’s filament drying table. Every density is a named product’s own technical data sheet figure rather than a generic chart value, which matters more than it sounds: see below.

Density is the number people get wrong

The density row names the product each figure came from, because two mainstream vendors do not agree and the disagreement is large enough to change a decision. Prusa publishes 1.24 g/cm³ for Prusament PLA; Polymaker publishes 1.17 g/cm³ for PolyLite PLA. On a 1 kg spool of 1.75 mm filament that is 335 m against 355 m, a 20 m gap from the brand alone.

ABS is the worst case, and it is worth being precise about it. The figure repeated across the hobby is 1.04 g/cm³, and Polymaker’s own summary table lists exactly that for PolyLite ABS, but the technical data sheet for that same product states 1.12 g/cm³. Those two numbers give 400 m and 371 m for the same spool, a 29 m disagreement inside one vendor’s own documentation. ASA splits similarly, at 1.07 for Prusament ASA against 1.13 for Polymaker ASA.

The practical rule: a density copied from any comparison table, this one included, is worth about ±6% on a length estimate. That is fine for deciding whether to open a new spool and not fine for deciding whether a 300 m print will finish. For that, read the data sheet for the exact spool and put the number into the filament weight and length calculator, which keeps the density field editable for precisely this reason. Filled and composite grades widen the spread further still, because filler loading is not standardised between brands.

PLA: the default, and correctly so

Prusa’s documentation calls PLA one of the easiest materials to print and notes it does not require a heated bed at all, with a melting point around 175 °C. It is not prone to significant warping, prints fast at low temperatures, and handles both small detailed models and objects filling most of the build volume.

The limits are equally well documented. PLA gets soft and deforms above roughly 60 °C, degrades under UV light, has weaker layer adhesion than other materials, and breaks along layers or into shards on impact. Prusa states plainly that it is not suitable for technical or outdoor use.

One widely repeated claim deserves a correction: PLA being plant-based does not make it compostable at home. Prusa’s documentation states it decomposes only in specialised composting facilities where temperatures exceed 80 °C, and that garden composting will not disintegrate it and will contaminate the soil with plastic microparticles.

Choose PLA when the part lives indoors at room temperature, detail and dimensional fidelity matter more than toughness, or the goal is a prototype that will be reprinted anyway.

PETG: the sensible default for parts that do a job

PETG occupies the middle ground and is the material most consumer printing should probably use more of. Prusa describes it as inexpensive with good printability, tenacious with good temperature resistance, and commonly used for mechanical parts, holders, clamps and waterproof parts thanks to strong layer adhesion. Its thermal expansion is very low, so it does not shrink or warp, which makes it viable for large flat models where PLA’s brittleness would be a problem and ABS’s warping would be fatal.

Two practical constraints follow it. The first is the build surface: Prusa strongly recommends a powder-coated textured or satin sheet and warns that printing PETG on smooth PEI may damage the sheet. The second is heat: parts are suitable for interior and most exterior use below about 80 °C, which is a real ceiling for anything left in a car.

On food contact, Prusa notes that although PETG itself is considered food-safe and is widely used in the food industry, it does not recommend PETG or any other filament for items in direct contact with food, because the layer grooves in any 3D print support bacterial growth. A food-safe coating and a stainless steel nozzle are the stated mitigations.

Choose PETG when the part is functional, will see mechanical stress or moderate warmth, or is large and flat enough that warping would ruin it.

ABS: capable, demanding, and conditional on hardware

Prusa describes ABS as a technical material with high tenacity and temperature resistance, suitable for mechanically stressed parts, whose surface can be smoothed with acetone. It also lists the drawbacks without softening them: significant warping, a required printer enclosure, and potentially dangerous fumes.

The enclosure is not optional and not a nice-to-have. ABS wants a high ambient temperature and a bed at least at 100 °C, and Prusa’s guidance is that the room should be well ventilated while avoiding any draught around the print, because a draught degrades the result. Those two requirements pull in opposite directions on an open-frame machine, which is exactly why enclosed printers exist. Among consumer machines the Bambu Lab P1S is a common enclosed option in this class; Bambu Lab’s own documentation also notes that its open-frame models, including the P1P, A1 and A1 mini, cannot be used for the chamber-heated filament drying procedure its enclosed machines support.

ABS parts used outdoors turn yellowish and more brittle over time because ABS lacks UV resistance. That is the specific problem ASA was created to solve.

Choose ABS when the printer is enclosed and ventilated, the part needs heat and impact resistance, or the finish will be acetone-smoothed.

ASA: the outdoor answer, one step up

Prusa positions ASA as the successor to ABS: more UV resistant, warping less, and smelling less, with temperature resistance up to 93 °C and solubility in acetone for smoothing. It runs slightly hotter at a 260 °C nozzle with a bed at 105 °C for the first layer and 110 °C after, and it still warps significantly enough that an enclosure is described as necessary for large parts.

If a part is going outdoors and must stay dimensionally sound in sunlight, ASA is the material, not ABS.

Pick by the part, not by the material

A short decision path covers most real cases.

• Indoors, decorative or a prototype, no heat load. PLA.
• A functional part, some stress, possibly damp, possibly large. PETG.
• Heat or impact resistance, and the printer is enclosed. ABS.
• Outdoors in sunlight, and the printer is enclosed. ASA.
• The printer is open-frame in a living space. PLA or PETG, and stop there.

The material that fails on the machine you actually own is not a strong material. An ABS bracket that warps off the bed at layer forty is weaker than the PETG one that finished.

The failure modes are different, and so are the fixes

PLA failures are usually temperature or cooling problems. PETG failures are usually adhesion problems in both directions: too little on the first layer, or so much that it damages the sheet. ABS failures are almost always thermal, meaning warping, layer splitting and corner lift caused by uneven ambient temperature.

One failure mode is shared by all three and is routinely misdiagnosed as a printer fault. Bambu Lab’s documentation describes moisture in filament vaporising rapidly inside the hot nozzle, causing the molten material to expand and extrude erratically, producing stringing, oozing, holes, rough surfaces and reduced strength. No amount of retraction tuning fixes a wet spool. If a material that printed cleanly last month is stringing now, drying temperatures and times by filament type is the place to start, and why moisture ruins otherwise good material covers the mechanism.

What this comparison does not settle

Published tensile and impact figures vary widely between brands within a single material family, because additives, colourants and fillers change them. A specific PETG can outperform a specific ABS on a specific test, and a carbon-filled grade behaves nothing like the unfilled polymer it is based on, including its density. Treat the table above as a guide to material families and the vendor data sheet as the authority for the spool in front of you.

For anyone choosing a first spool rather than choosing between three, what to buy for a first filament purchase narrows the decision further.