Empty Filament Spool Weight by Brand: Tare Table and Meters-Left Calculator

Subtract the wrong tare and your "100 g left" is really 75 g. That is the gap between a finished print and spaghetti at 3 a.m.

Our view: when a brand publishes no spool weight, don't trust any tare figure you didn't weigh yourself. Use the table below as a starting point. Your own empty spool is the proof.

How much does an empty filament spool weigh, brand by brand?

Most spools weigh within a narrow band. Gough's Tech Zone measured a batch of reels and found most were about 195 to 200 mm across and weighed 186 to 201 g. The outlier was an Anycubic spool (possibly rebranded SUNLU) at just 127 g.

The heavyweights are the Bambu Lab spools. A Bambu Lab Community Forum user weighed three of them empty:

• White spool (70°C rated): 245 g
• Light grey spool (90°C rated): 253 g
• Transparent spool (70°C rated): 255 g

Those numbers include the cardboard center core, which weighs 37 to 38 g on its own.

Nearly every figure is a community measurement, not a manufacturer spec. Polymaker, Elegoo, Overture and Hatchbox have no sourced figure, so for those the scale on your kitchen counter is the only honest source.

One more trap: matching size doesn't mean matching weight. Gough's Tech Zone found that inner hole and outside width vary a lot from spool to spool. Two spools that look the same in the AMS can still differ by tens of grams.

Is a cardboard spool lighter than a plastic spool from the same brand?

Yes, and by more than most people expect.

• eSun: cardboard about 170 g, clear plastic 209 to 225 g
• MG Chemicals: cardboard about 150 g, black plastic 239 g (narrow) and 250 g (wide)
• SunLu: clear "lightweight" plastic 139 g, black plastic about 220 g

Switching from plastic to cardboard saves roughly 40 to 100 g. Plastic isn't one number either. SunLu's two plastic spools are about 80 g apart, more than the gap between many cardboard and plastic spools from other brands.

According to filamentcalcs.com, many current eSun PLA lines ship on cardboard. If you used to print eSun on clear plastic, check which spool is on your shelf before you pick a row. It's an easy 40 g mistake.

What do 250 g, 500 g and 2 kg spools weigh empty?

Smaller filament doesn't mean a lighter spool. An eSun black 0.5 kg spool measured 212 g empty, as heavy as many 1 kg plastic spools. Half the filament, same chunk of plastic.

Some small spools really are light. A Creality 200 g spool weighed 104 g on the 3dprintingspace.com community list, and a CCTREE spool weighed 111 g, according to a V1E.com forum user. At the other extreme, a Dupont clear 1 kg spool weighed 360 g empty on the same 3dprintingspace.com list.

Weigh any 2 kg spool empty before you trust a number for it.

Free sample spools cause their own trouble. A Bambu Lab forum user said the 250 g sample that came with their printer held over 350 g of filament. Nice surprise, but "250 g minus whatever's left" gives you the wrong answer anyway.

What does an empty Bambu Lab spool weigh compared with refill and cardboard versions?

The Bambu plastic spool weighs 245 to 255 g empty, depending on the variant, and that includes the 37 to 38 g cardboard core. The spread across the three versions measured is 10 g, so even within Bambu, a different design means a different tare.

• Cardboard spool: brown pressed-board flanges and a cardboard core, matte and light in the hand. Use the brand's cardboard row (eSun about 170 g, MG Chemicals about 150 g).
• Plastic spool: molded flanges, usually clear, black or grey, often with a separate core inside. Bambu's version has a cardboard core inside plastic flanges. Use the brand's plastic row.
• Refill on a reusable spool: the refill arrives as a coil with no flanges. You mount it on a reusable spool you already own. Its tare is that reusable spool, which you weigh once and use for every refill after.

According to a user on the Bambu Lab Community Forum, Bambu lists the empty spool weight under the specifications on each roll's store page. Check the page for the exact roll you bought, because the spool has changed between variants. One user who buys hundreds a year says none has been off by more than a couple of grams of filament.

Does the 1 kg on the label include the spool?

No. "1 kg" means the filament. The box rarely prints the spool's weight, so you get the net weight and have to guess the rest.

The common workaround is to weigh a new roll and subtract 1000 g. A Bambu Lab forum user who does this calls the result approximate, and notes that most companies give slightly more than 1 kg. Gough's Tech Zone points out the catch: the amount wound onto a spool is never exact, so this method can overestimate or underestimate the tare.

How far off can it be? A V1E.com forum user weighed two new 3D Solutech rolls and found they differed by up to about 100 g. That may have been the filament, not the spool. So subtracting 1000 g is a rough check, not a tare.

How do I work out how much filament is left using a kitchen scale?

You don't need a lab scale. A kitchen scale that reads in whole grams is enough.

1. Take the spool off the printer or out of the AMS.
2. Set it on a kitchen scale on a flat surface.
3. Read the weight in grams.
4. Subtract the empty spool weight from the table, or the one you weighed yourself.
5. Multiply the grams left by about 0.334 to get meters of 1.75 mm PLA.

Worked example. Your used eSun spool reads 475 g. It's cardboard, so the tare is about 170 g. 475 minus 170 leaves 305 g of filament. At 0.334 m per gram, that's about 102 m of 1.75 mm PLA.

3Dfils, which publishes the 334 m per kg figure for 1.75 mm PLA, notes that its meter values are approximate. The grams are what you can measure. Treat the meters as a close estimate.

Your slicer already estimates how many grams each print needs, so compare that number with your grams left. PrusaSlicer lets you store an empty spool weight for each filament profile, which saves you the subtraction next time.

How many meters are left, and is 50 grams enough for my next print?

Enter four numbers in the calculator: your scale reading, the tare, the material's density and the filament diameter. It gives you the meters left. Grams left is just the scale reading minus the tare.

Density is what changes meters per gram between materials.

• PLA: about 1.24 g/cm³, about 335 m per kg

Check the technical data sheet for your exact filament, since blends and fillers change these numbers.

Is 50 g enough? 50 g of 1.75 mm PLA is about 16.7 m. That covers a small bracket or a test cube. It won't finish a 60 g print. Leave headroom on top of the slicer estimate for purge, a skirt or brim, and the first layer you restart. On a multicolor setup, purge waste can eat a lot of that 50 g.

What if my brand isn't listed, and how do I measure tare myself?

Weigh it yourself. Gough's Tech Zone calls weighing empty spools the best method, because brand databases fall behind as filament gets rebranded and new variants appear. If Anycubic may be selling SUNLU spools, a brand name doesn't tell you the spool.

Here's how to do it right:

• Finish the spool, or unwind the last few meters into a bag.
• Weigh it the way it sits on the printer. Keep the cardboard core in if it doesn't come out, and remove clips every time or never.
• Write the weight in marker on the flange.
• Enter it in your slicer's filament profile and in the calculator above.

If you want to help others, the community project onlyspoolz collects measured empty spool weights.