1.8 to 3.0 cents a gram, from the $18 to $30 a kilogram PETG occupies at mainstream retail. A mid-range spool at $24 works out at 2.4 cents a gram.
That is a modest premium over PLA on the shelf. In use it is slightly worse than it looks, and the reason is density rather than price.
The same part costs more than the sticker suggests
PETG is denser than PLA — 1.27 g/cm³ against 1.24 for the common headline figures. Print an identical model in both and the PETG one comes out 2.4% heavier, because the geometry is fixed and the mass follows the polymer.
So a like-for-like comparison prices the volume, not the mass:
- PLA at $22/kg — about 2.7 cents per cubic centimetre of part
- PETG at $24/kg — about 3.0 cents per cubic centimetre of part
The gap on the shelf is roughly nine percent; the gap on the finished part is nearer twelve. Neither is large, but the per-gram figure is the one that understates it.
Length, if you are measuring off the reel
One metre of 1.75 mm PETG weighs 3.05 g, against 2.98 g for PLA. A kilogram gives you 327.36 m rather than 335.28 m — about eight metres less filament in the same box.
That matters if you judge a spool by eye. Two reels wound to the same visible diameter are not carrying the same mass, and the denser material runs out first.
What actually makes PETG cost more than PLA
Not the spool price. PETG needs drying where PLA usually does not; it is far fussier about first-layer squish and stringing; and the settings window between "bonds properly" and "sticks to the bed permanently" is narrower. The cost shows up as failed attempts and reprints, not as cents per gram.
If your PETG failure rate is meaningfully higher than your PLA failure rate — and for most people starting out it is — that difference swamps the two-cents-a-gram question entirely. A 20% failure rate multiplies your real per-part cost by 1.25.
Price a specific part in both materials with the print cost calculator, or read what else changes between them in PLA vs PETG.