PLA vs PETG: heat, toughness, plates and printing, compared from the data sheets
Short answer
Choose PLA for detail, easy printing and indoor models; choose PETG when a part must survive warmth, impact or the outdoors. In the three makers' data sheets compared here, standard PLA deflects at 55–60 °C under a 0.45 MPa load and PETG at 68–71 °C [6, 8, 7, 5]. Prusa describes PLA as brittle with weaker layer adhesion, and PETG as tough with a tendency to string [1, 2].
The short version, in numbers
The table compares each maker’s standard PLA with its standard PETG. All values are as published; HDT is the heat deflection temperature under a 0.45 MPa load, the gentler of the two loads the data sheets report.
| Product | Nozzle °C | Bed °C | HDT at 0.45 MPa | Tensile, XY | Drying |
|---|---|---|---|---|---|
| Bambu PLA Basic | 190–230 | 35–45 | 57 °C | 35 MPa | 50 °C, 8 h [4] |
| Bambu PETG Basic | 230–260 | 65–75 | 71 °C | 51 MPa | 65 °C, 8 h [5] |
| Prusament PLA | 200–220 | 40–60 | 55 °C | 51 MPa | see note [6] |
| Prusament PETG | 240–260 | 70–90 | 68 °C | 47 MPa | see note [7] |
| Polymaker PolyLite PLA | 190–230 | 25–60 | 60 °C | 52.3 MPa | 55 °C, 6 h [8] |
| Polymaker PETG | 240–260 | 60–70 | 69 °C | 47.96 MPa | 60 °C, 6 h [9] |
The Prusament data sheets do not give drying conditions; Prusa’s drying guide lists 45 °C for 6 hours for PLA and 55 °C for 6 hours for PETG (see the drying chart).
Two patterns stand out. PETG is printed 30–50 °C hotter on the nozzle and much hotter on the bed. And PETG’s heat deflection is higher by 9–14 °C, while the tensile figures overlap: in two of the three pairs, the PLA’s published tensile strength is equal to or higher than the PETG’s. Tensile strength is not the reason to choose PETG.
Heat: the most common reason to switch
Prusa’s guide says PLA gets soft and deforms above about 60 °C [1], which matches the 55–60 °C HDT values above. That rules PLA out for a car interior in summer, a part near a motor or a lamp, or anything left in direct sun. Prusa rates PETG parts for indoor and most outdoor use below 80 °C [2].
The data sheets measure HDT on test bars under a specified load (ISO 75 in Bambu Lab’s and Polymaker’s sheets [4, 9]), so treat the numbers as a ranking, not a guarantee that a printed part holds its shape up to that temperature. Thin walls, sparse infill and constant load all lower the real limit. The heat resistance comparison lists every value in the database, including the stiffer 1.8 MPa results.
Toughness and how parts fail
Prusa describes PLA as brittle and inflexible, with weaker layer adhesion than other materials, breaking along layers or into shards on impact [1]. It describes PETG as tenacious, with great layer adhesion and enough flexibility that parts often do not break [2]. In practice: PLA is stiff and snaps; PETG bends first.
The Z-direction values (strength across layers) support the layer-adhesion point where makers publish them. Polymaker lists 52.3 MPa XY and 40.5 MPa Z for PolyLite PLA, and 47.96 MPa XY and 45.71 MPa Z for its PETG [8, 9]: the PETG loses much less strength between layers.
Printing differences
Bed and plate. PLA needs little or no bed heat: Bambu Lab lists 35–45 °C on its Cool Plate [3]. PETG needs 60–80 °C on Bambu’s plates, and Bambu does not recommend its Cool Plate for PETG [3]. The bigger trap is adhesion that is too good: Prusa warns that PETG can bond so strongly to a smooth PEI sheet that it damages the sheet, and recommends a textured or satin sheet, or a glue stick as a separator on smooth PEI [2]. See bed adhesion.
Stringing. Prusa lists stringing among PETG’s drawbacks and suggests higher retraction and lower nozzle temperature, while noting that PLA is sometimes prone to stringing too [2, 1]. If PETG strings badly, check moisture first; see stringing.
Cooling. PLA wants strong part cooling. For PETG, Prusa recommends the first few layers without the fan and then about half fan power, and says to turn the fan off entirely if maximum toughness matters more than detail [2].
Bridges and detail. Prusa lists poor bridging and overhangs, and weaker fine detail, as PETG drawbacks [2]. PLA is the better choice for figures and crisp small features.
Enclosed printers. Heat around the printer works against PLA. Bambu Lab’s guide says filaments that soften below 60 °C, such as PLA, can soften in the extruder if the chamber gets warm, and recommends opening the door or removing the top glass when the bed is above 45 °C; it gives the same advice for PETG above a 60 °C bed [3]. For PETG it also recommends an enclosed printer, so that cold surroundings do not weaken layer bonding [3].
Speed
Both materials come in standard and high-flow versions, so the material name alone does not decide speed. Polymaker, for example, publishes a recommended maximum volumetric speed of 15 mm³/s for PolyLite PLA and 24 mm³/s for its high-speed PolySonic PLA [10]. Compare the published limits on the max volumetric speed page and see high-speed PLA.
Which one to load
| If the part… | Choose |
|---|---|
| is a figure, display model, prototype or cosplay piece | PLA |
| has fine detail, sharp edges or long bridges | PLA |
| will sit above about 55 °C, in a car or in sun | PETG (or ASA for long outdoor life) |
| must flex, clip, or survive a drop | PETG |
| will be outdoors | PETG for moderate use; Prusa notes PLA degrades under UV [1] |
Neither is meant for food contact as printed: Prusa recommends against printing dishes in any filament because layer grooves can harbour bacteria [1, 2].
Questions
Is PETG stronger than PLA?
It depends on which strength. Several data sheets list similar or even higher tensile strength for PLA; Prusament PLA lists 51 MPa against 47 MPa for Prusament PETG [6, 7]. PETG's advantage is toughness: Prusa calls PLA brittle and says it breaks along layers or into shards on impact, while PETG's tenacity and flexibility often prevent it from breaking [1, 2].
Sources
- PLA. Prusa Knowledge Base. Manufacturer documentation. Properties, softening above 60 °C, UV degradation, brittleness, recommended temperatures. Accessed October 12, 2026.
- PETG. Prusa Knowledge Base. Manufacturer documentation. Properties, stringing, cooling, smooth PEI warning, use below 80 °C. Accessed October 12, 2026.
- Filament guide: printer, nozzle, AMS, build plate, glue compatibility and required parameters. Bambu Lab Wiki. Manufacturer documentation. Enclosure needs by material, plate compatibility and bed temperatures, chamber heat and softening. Accessed October 12, 2026.
- Bambu PLA Basic Technical Data Sheet (V3.0). Bambu Lab. Technical data sheet. Accessed October 12, 2026.
- Bambu PETG Basic Technical Data Sheet (V3.0). Bambu Lab. Technical data sheet. Accessed October 12, 2026.
- Prusament PLA Technical Datasheet (v1.1, 27-07-2022). Prusa Polymers. Technical data sheet. Accessed October 12, 2026.
- Prusament PETG Technical Datasheet (v1.1, 16-02-2022). Prusa Polymers. Technical data sheet. Accessed October 12, 2026.
- PolyLite PLA Technical Data Sheet (V5.4). Polymaker. Technical data sheet. Accessed October 12, 2026.
- Polymaker PETG Technical Data Sheet (V3.0). Polymaker. Technical data sheet. Accessed October 12, 2026.
- Polymaker Material Print Tips. Polymaker Wiki. Manufacturer documentation. Recommended maximum volumetric speeds per product. Accessed October 12, 2026.