PLA Filament Cost Calculator

Turn your spool price into a cost per gram, a cost per print, and a realistic number of prints per spool.

Cost per gram and per print

Spool price ($)

Spool weight (g)

Filament only, not the spool.

Grams per print

Waste / purge (%)

Purge towers, prime blobs, failed starts.

Cost per gram	—
Filament per print (incl. waste)	—
Material cost per print	—
Prints per spool	—
Material cost for 100 prints	—

Why cost per gram is the number that matters

Filament is sold by the spool but consumed by the gram. Until you convert one into the other you cannot price anything, because the slicer reports consumption in grams and your supplier invoices you in spools. The conversion is one division, and it is the single most useful number on any print farm's wall.

cost per gram   = spool price ÷ spool weight in grams
cost per print  = cost per gram × grams used × (1 + waste ÷ 100)
prints / spool  = spool weight ÷ (grams per print × (1 + waste ÷ 100))

A $22/kg spool works out to 2.2 cents per gram. An 85 g part therefore uses about $1.87 of plastic, or $1.98 once you allow for six percent of waste. That is material only — the full cost of the part also includes power, wear and your time, which the main 3D print cost calculator adds on top.

Typical weights for common prints

If you do not yet have slicer output for a part, these ballpark figures are a reasonable starting point before you run the real estimate.

Part	Typical filament	Notes
Benchy (calibration boat)	12 – 16 g	The standard test print; useful as a reference unit.
Phone stand	60 – 120 g	Varies hugely with wall count and infill.
Articulated figure	30 – 70 g	Printed in place, low infill.
Vase mode container	40 – 90 g	Single wall; cheap and fast.
Mechanical bracket	80 – 200 g	Higher infill for strength.
Replacement gear	15 – 45 g	Small but often needs PETG or nylon.

These are indicative only. Wall count, infill percentage and supports move the number far more than material choice does — dropping infill from 40% to 15% routinely halves the filament in a part.

Where the filament you paid for actually goes

Not every gram on the spool ends up in a sellable part. Four destinations account for the difference between what you buy and what you ship:

Purge and prime. Every nozzle change and every start-up extrudes plastic that is thrown away. On a single-colour printer this is small; with a multi-material unit it can be a large fraction of the job.
Supports. Structurally necessary and always discarded. Tree supports usually waste less than dense grid supports.
Failed prints. Budgeted separately in the main calculator, because a failure consumes the whole part rather than a percentage of it.
Moisture and brittle filament. PLA that has absorbed water snaps mid-print. The grams are gone either way, and drying is far cheaper than replacing spools.

Six percent is a fair default for a single-material bed slinger. If you run a multi-material setup with purge towers, measure it rather than guessing — it is often twenty percent or more.

How to cut filament cost without hurting the part

Reduce infill before you reduce walls. Perimeter count drives strength; infill mostly drives weight. Going from 40% to 15% infill with an extra perimeter is usually both stronger and cheaper.
Use adaptive layer heights. Fine layers only where the surface is visible, coarse layers where it is not. Shorter print time also means less power.
Choose tree supports. Less material, less cleanup time, and fewer scars on the surface.
Buy in volume only for your top two materials. A bulk discount on a colour you print twice a year is storage, not saving.
Weigh your spools when they arrive. A "1 kg" spool that weighs 940 g of filament changes your cost per gram by six percent before you print anything.

Frequently asked questions

How much does 1 kg of PLA cost?

Typically between $18 and $25 for a decent hobby or prosumer brand, with premium formulations and specialty colours reaching $35. Bulk reels are cheaper per kilogram but require dry storage and a holder that can take the weight.

Is PLA cheaper than PETG?

Usually slightly, but the gap is small compared with the other costs in a print. PETG's advantage is durability and heat resistance; if a PLA part fails in a hot car you have saved nothing. Choose on the part's requirements, then price accordingly.

How many prints can I get from one spool?

Divide the spool weight by the grams per print including waste. A 1 kg spool at 85 g per print with 6% waste gives roughly eleven parts. Small calibration prints will of course yield hundreds.

Should I charge customers for the waste?

Yes, indirectly — that is what the waste percentage field is for. If you quote on clean filament weight alone you absorb the purge and the supports yourself, which on multi-material jobs can be a significant slice of the order.