Empty spool weights
Bambu Lab empty spool weight: reusable spool, refill core, cardboard
Bambu Lab does not print the empty weight on the spool, so everyone ends up guessing. The right number depends on which spool you are actually weighing, because Bambu has shipped at least three different setups.
If you run refills on the reusable spool, your scale is seeing the plastic spool plus the refill's cardboard core. That combination is about 233 g. If you bought filament that came on a full cardboard spool, the spool alone is about 205 g. The older gen-1 transparent spools are heavier than the current light-grey ones, so if your math looks off by 40 to 60 g, that is probably why.
Bambu Lab spool weights at a glance
| Spool | Empty weight (g) | Notes |
|---|---|---|
| Reusable spool (light-grey, current) | ~208 | Bare spool, no cardboard core. Four community-measured spools all landed at 208 to 208.5 g. |
| Reusable spool + refill core | ~233 | What the scale sees with a refill mounted: spool plus the ~25 g cardboard core. |
| Reusable spool (gen-1 transparent) | 250-264 | The older clear spool with clips. White version ~251 g, transparent ~264 g. |
| Cardboard spool (filament with spool) | ~205 | The all-cardboard spool Bambu filament ships on when you don't buy refills. |
Spools vary a few grams batch to batch, so treat these as good starting points. The exact answer takes one minute: weigh an empty spool of the type you use, write the number on it with a Sharpie, and pick Custom in the calculator from then on.
How to weigh it right
- Take the spool off the printer or out of the AMS. Anything supporting the spool skews the reading.
- Use a kitchen scale on a flat surface. Gram resolution is plenty; you do not need a lab scale.
- Enter the total weight above, pick the matching spool type, and read off grams remaining. The result updates as you type.
Frequently asked
- Why doesn't Bambu Lab print the spool weight on the spool?
- No idea, and the community keeps asking them to. Until they do, weigh one empty spool of each type you own and write the number on it with a Sharpie. These presets get you close, but your own measurement is exact.
- How much does the refill cardboard core weigh on its own?
- About 25 g. That is why the reusable spool reads ~208 g bare but ~233 g with a refill mounted. If you weigh a spool mid-print with a refill on it, use the 233 g figure.
- Can I weigh the spool while it's in the AMS?
- No, take it out. The AMS rollers support part of the spool's weight, so anything you read while it is docked is meaningless. Pull the spool, weigh it on a kitchen scale, put it back.
- Do the high-temp and low-temp reusable spools weigh the same?
- Close but not identical. The current light-grey low-temp spool measures ~208 g. The older transparent high-temp version runs 250 to 264 g depending on the clips. If you still have gen-1 spools in rotation, weigh one and label it.
Where these numbers come from
Community measurements and crowdsourced spool databases, cross-checked in July 2026. If your spool disagrees, trust your scale over any table, including this one.