3D-Fuel filament ships on three spool sizes: 1 kg, 4 kg, and 25 lb (11.3 kg). This article is our reference for the dimensions and empty weights of every spool we use now and have used in the past.
Our current 1 kg spool
Since November 2025, our 1 kg filament ships on a lighter AMS-compatible spool made from recycled HIPS. It uses 29% less plastic than the spool before it and has a smaller 85 mm core, which keeps the filament clear of the inlet on AMS-style systems.
- Fits the Bambu Lab AMS and AMS 2 with the lid closed and latched.
- Works in all four positions of the AMS Lite.
- Tested in AMS-style units from other brands and in a range of filament dryers.
We've used AMS-compatible 1 kg spools since October 2023, and effectively all of our inventory has shipped on them since April 2025 unless a product page says otherwise. Our older 1 kg spools fit in the AMS but didn't let the lid latch shut.
Have a notched spool? Print a notch cover ring
For a short time in late 2025, this spool had a notch in the flange to allow automatic winding on our production lines. The notch works fine on rollers around 8 mm in diameter, which most AMS units and dryers use. On spool holders with much smaller rollers (about 4 mm), like the Creality Space Pi, the notch can catch, knock the spool out of alignment, and trigger an extruder motor overload error.
We now use a notchless version of the same spool, so new orders don't have this issue.
If you have a notched spool, this clip-on ring covers the notch and still fits in the AMS and AMS 2 without dragging: Download the spool notch cover ring. Each ring uses less than 7 g of filament and prints in under half an hour. Print it in PETG or Pro PCTG so it holds up to 65°C drying.
How much filament is left on my spool?
Weigh the spool in grams and subtract the empty spool weight from the table below. What's left is the approximate weight of filament on the spool.
- A full 1 kg spool on our current spool weighs about 1,155 g.
- A full 1 kg spool on the 2023–2025 spool weighs about 1,225 g.
- A full 1 kg spool on our old spool weighs about 1,265 g.
- A full 4 kg spool weighs about 4,920 g.
Not sure which 1 kg spool you have? Measure the core: 85 mm is the current spool, 105 mm is the 2023–2025 spool, and 95 mm is the old spool.
Spool dimensions and weights
| Measurement | Current 1 kg spool (AMS compatible) | 2023–2025 1 kg spool (AMS compatible) | Old 1 kg spool | 4 kg spool | 25 lb (11.3 kg) spool |
|---|---|---|---|---|---|
| Dates of use | Nov 2025 – present | Oct 2023 – Oct 2025 | Before Oct 2023 | Current | Current |
| d1) Flange diameter | 200 mm / 7.87" | 200 mm / 7.87" | 202 mm / 7.93" | 298.5 mm / 11.75" | 406 mm / 16" |
| L1) Outside width | 68 mm / 2.68" | 68 mm / 2.68" | 69 mm / 2.72" | 101.6 mm / 4.0" | 210 mm / 8.25" |
| L2) Traverse (inside) width | 60.5 mm / 2.38" | 59 mm / 2.32" | 60 mm / 2.36" | 91.4 mm / 3.6" | 178 mm / 7" |
| d2) Barrel (core) outer diameter | 85 mm / 3.35" | 105 mm / 4.13" | 95 mm / 3.75" | 128.2 mm / 5.046" | 213 mm / 8.375" |
| d3) Arbor (center) hole diameter | 52.1 mm / 2.05" | 52 mm / 2.05" | 54 mm / 2.12" | 52.4 mm / 2.063" | 30.5 mm / 1.2" |
| Empty spool weight | 155 g / 5.5 oz | 225 g / 7.9 oz | 266 g / 9.3 oz | 920 g / 2.0 lb | n/a |
| Spool material | Recycled HIPS | Recycled ABS | HIPS | HIPS | — |
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