Which PLA is worth buying

What this page will not do

This page will not name a best brand, and that is deliberate. A brand ranking is only meaningful if someone measured a representative sample of spools across a production run, across suppliers and across time, and published the method. We have not done that, and repeating a ranking from someone else would be inventing a fact.

What we can do is tell you which specifications actually change how a spool prints, so you can judge any brand on evidence you can check in ten minutes with the tools you already own.

Diameter tolerance: the one specification that matters most

Filament diameter variation is the single most useful published number, and it is the one most sellers omit. A spool that claims 1.75 mm is never exactly 1.75 mm all the way through; the question is how far it wanders.

Tighter tolerance means more consistent extrusion, fewer blobs, and less need to compensate in the slicer. Widely varying diameter behaves like a constantly changing flow rate, which shows up as inconsistent walls and occasional under-extrusion.

You can check it yourself without trusting the label: measure across the filament at ten points along a few metres with digital calipers and look at the spread, not the average.

What you measure	What it means in practice
Spread under 0.04 mm	Consistent enough that you will not notice it
Spread 0.05 – 0.10 mm	Usable, but expect occasional blobs or thin walls
Spread over 0.10 mm	Visible inconsistency; a candidate for returning

Fill accuracy: what you actually get on the spool

The stated net weight is a target with a tolerance, and the tolerance is not always honoured in your favour. A spool sold as 1 kg that arrives 60 g light costs you 6% on every calculation you run from it — more than the electricity line on most prints.

Weigh one full spool per brand, once. Note the number. If a brand consistently runs short, that is a fact about that brand you established yourself in one minute, and it is worth more than any review.

Related: weigh an empty spool of each brand you use, because the spool remaining calculator needs it and empty spool weights vary by more than people expect.

Winding, spool design and storage

Three things that never appear on a specification sheet but decide whether a spool is pleasant or infuriating to use:

• Winding quality. Tight, even, non-crossing winding means no tangles and no mid-print stalls. Loose or overlapping winding fails near the end of a spool, which is exactly when you are not watching.
• Spool geometry. Hub hole diameter, outer diameter and edge width determine whether the spool fits your holder, your dry box or a multi-material system. A cheap spool that does not fit your setup is an expensive spool.
• Refillability and cardboard versus plastic. Cardboard cores are lighter and compostable but can absorb moisture; plastic spools are heavier and reusable. Both affect your empty-spool weight and therefore your remaining-filament arithmetic.

Storage matters more than brand. A perfect spool left open for six months in a humid room prints worse than a mediocre one kept sealed with desiccant.

Brittleness, colour and batch consistency

Two further things worth tracking once you settle on a supplier:

Age brittleness. Old PLA snaps. If a spool that printed cleanly starts breaking at the extruder, the answer is usually age and moisture rather than a bad batch, and drying helps only partially. Date your spools when you open them.

Colour consistency between batches. If you sell finished items in a colour, order in larger batches and record the batch. A slightly different pigment between two orders is visible on a shelf next to each other, and it is the kind of thing that makes a product look inconsistent rather than hand-made.

A buying checklist you can run in ten minutes

Before you commit a repeat order to a supplier:

• Weigh one full spool and compare with the stated net weight.
• Measure diameter at ten points and note the spread, not the average.
• Check the spool fits your holder and dry box before ordering ten of them.
• Print one familiar test model and compare it against your reference print.
• Date the spool, then weigh an empty one when it runs out and write the number down.

Five measurements, about ten minutes, and you have a supplier file built from evidence rather than from marketing copy.

Important assumptions

No brand, price or performance figure on this page is a recommendation or a measurement of any specific product. The tolerance thresholds in the table are practical rules of thumb, not standards.

Prices are not quoted here at all, because filament pricing varies by country, by shipping route and by season, and a figure published today would be misleading within weeks. Use your own receipts and the filament cost calculator.