GUIDES › PLA VS PETG
MATERIAL COMPARISON
PLA VS PETG
An honest comparison of the two most common FDM filaments. Both have their place — the right choice depends on what your part is for and where it'll live.
AT A GLANCE
QUICK OVERVIEW
PLA — POLYLACTIC ACID
The default filament for most prints. Easy to print, biodegradable, looks great.
• Glass-transition: ~60°C
• Tensile strength: ~50 MPa
• Stiff, brittle (snaps before bending)
• Stable indoors, fades / softens outdoors
• Easiest to print — no warping
• Wide colour range, including matte and silk
PETG — POLYETHYLENE TEREPHTHALATE GLYCOL
The functional default. Tougher, more flexible, weather-resistant — at the cost of a slightly trickier print.
• Glass-transition: ~80°C
• Tensile strength: ~50 MPa (similar to PLA but tougher)
• Tough, flexes before breaking
• UV-resistant, holds up outdoors
• More demanding to print — stringing, bed adhesion
• Good chemical resistance (acids, alcohols, oils)
HEAD TO HEAD
DETAILED COMPARISON
| PROPERTY | PLA | PETG |
|---|---|---|
| EASE OF PRINTING | Easiest filament to print. No enclosure needed. Sticks well to most beds. Fast print speeds possible. ADVANTAGE: PLA | More demanding. Prone to stringing without retraction tuning. Bed adhesion sometimes inconsistent. Slightly slower print speeds. |
| IMPACT STRENGTH | Brittle. Snaps under sudden force. Prints can shatter on a drop. | Tough. Flexes before breaking. Survives drops far better. ADVANTAGE: PETG |
| TENSILE STRENGTH | ~50 MPa. Stiff and rigid until it cracks. | ~50 MPa. Similar yield, much higher elongation at break. ADVANTAGE: PETG |
| HEAT RESISTANCE | Softens at ~60°C. Will deform on a sunny dashboard. | Holds up to ~80°C. Survives most indoor + many outdoor environments. ADVANTAGE: PETG |
| OUTDOOR DURABILITY | Degrades in UV. Fades, gets brittle, eventually fails. | UV-resistant. Holds up for years outdoors. ADVANTAGE: PETG |
| CHEMICAL RESISTANCE | Poor. Affected by alcohols, oils, mild solvents. | Good. Resists alcohols, oils, mild acids — used for food containers commercially. ADVANTAGE: PETG |
| SURFACE FINISH | Smooth, glossy or matte depending on filament type. Sanding straightforward. ADVANTAGE: PLA | Slightly stringy off the printer; prone to small surface defects. Sanding harder (gummy). |
| DIMENSIONAL ACCURACY | Excellent. Low shrinkage. Tight tolerances reproducible. ADVANTAGE: PLA | Good but slightly more variable. Stringing can affect fit on tight features. |
| WEIGHT | Slightly denser than PETG. | Slightly lighter than PLA. BOTH SIMILAR |
| COST | The cheapest mainstream filament. ~£15-25/kg. ADVANTAGE: PLA | Modestly more expensive. ~£20-30/kg. |
| POST-PROCESSING | Sands cleanly. Paints well with acrylic + primer. Glues with cyanoacrylate. ADVANTAGE: PLA | Sanding is gummy. Paints decently. Glues better with PETG-specific cement or epoxy. |
| SUSTAINABILITY | Plant-based (corn/sugarcane). Biodegrades industrially under specific conditions (not in landfill). | Petrochemical-derived. Recyclable but rarely recycled in consumer streams. BOTH SIMILAR |
Both are great filaments. The choice usually comes down to whether the part will see impact, heat, or weather.
COMMON MISCONCEPTION
IS PETG ACTUALLY STRONGER THAN PLA?
On paper their tensile strength is almost identical. The real difference is what happens when the part gets dropped, heated, or left in the sun.
WHERE PETG WINS
• Impact resistance — flexes and absorbs energy instead of shattering
• Elongation at break — ~5-10% vs PLA's ~2-4%
• Long-term load tolerance — PLA creeps under sustained stress, PETG less so
• Heat tolerance — your part won't deform on a hot day
WHERE PLA HOLDS UP
• Tensile strength is comparable (both ~50 MPa)
• Stiffness — PLA is stiffer until it cracks
• Dimensional accuracy under load — PLA holds tolerance better
• Print quality — fewer print artefacts means a stronger as-printed part
Bottom line: For functional parts that see impact, repeated stress, heat, or weather — PETG. For visual parts, prototypes, miniatures, models, and indoor decorative items — PLA. Both have ~50 MPa tensile strength on paper; the difference is what happens when the part gets dropped, heated, or left in the sun.
CHOOSE YOUR FILAMENT
DECISION GUIDE
CHOOSE PLA WHEN...
• The part is for indoor display or use
• Visual finish matters (miniatures, models, gifts)
• You're prototyping form / fit / appearance
• Cost is the primary driver
• You're new to 3D printing and want easy success
• The part won't see impact, heat, or sustained load
• You need a wide colour palette (including matte/silk)
CHOOSE PETG WHEN...
• The part needs to survive drops or impacts
• It'll live outdoors or in a hot environment (cars, garages, summer sun)
• Mechanical strength matters — brackets, mounts, functional fixtures
• It'll be exposed to oils, alcohols, or mild chemicals
• It's a part that gets handled or stressed repeatedly
• You're making something that needs to last years not months
• The part is structural rather than aesthetic
If you're not sure, default to PLA — it's easier, cheaper, and prints first time. Move to PETG when the use case demands it.
WHEN WE PICK WHICH
REAL-WORLD EXAMPLES
PLA
• Translucent book-shelf lamps and decorative indoor lighting
• Tabletop miniatures and figures (detail + colour, indoor)
• Architectural site models (visual prototypes, presentation use)
PETG
• Engineering bracket prototypes (functional load testing)
• Caravan / van interior fixtures (UV exposure, daily use)
• Mounting clips and structural fittings
DON'T USE EITHER WHEN
• The part needs to survive >80°C continuous heat (use ABS / ASA / polycarbonate)
• The part is in direct sustained UV outdoors for years (use ASA)
• The part needs to flex significantly without breaking (use TPU)
PRICING
COST COMPARISON
| PART | VOLUME | PLA COST | PETG COST |
|---|---|---|---|
| Small bracket (50×30×20mm) | ~5cm³ | from £5 | from £6 |
| Medium enclosure (120×80×40mm) | ~30cm³ | ~£15-20 | ~£18-25 |
| Large display piece (200×150×100mm) | ~150cm³ | ~£40-60 | ~£50-75 |
Prices indicative — actual quote depends on infill, layer height, supports, dispatch. Get an instant quote at /quote.
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