Filament Spool Sizes, Weights & Dimensions
How big is a 1 kg filament spool? How much does the empty spool weigh? How many meters of filament are on a roll? How much is in a sample coil? Here are quick answers, plus the exact dimensions of every Atomic Filament spool.
Atomic Filament Spool Sizes & Dimensions
| 1 kg AMS-Compatible Spool | 3.5 kg Jumbo Spool | |
|---|---|---|
| Filament weight (net) | 1 kg (1,000 g / 2.2 lb) | 3.5 kg (3,500 g / 7.7 lb) |
| Spool outer diameter | 7 7/8 in (200 mm) | 12 in (305 mm) |
| Spool width (thickness) | 2 5/8 in (67 mm) | 3 3/4 in (95 mm) |
| Center hole (arbor/hub) | 2 in (51 mm) | 2 in (51 mm) |
| Empty spool weight | 0.26 kg (260 g) | 0.936 kg (936 g) |
| Full spool weight (approx.) | 1.26 kg (2.8 lb) | 4.44 kg (9.8 lb) |
| Bambu AMS compatible | Yes | No (use an external spool holder) |
| Spool return credit | $2 | $3 |
Our 1 kg spools were redesigned to fit and feed in the Bambu Lab AMS. The new spool also uses about 30% less plastic and fits most other printers' spool holders. Every 1 kg Atomic spool, in every material and color, uses this spool.
The 3.5 kg jumbo spools are built for big prints and print farms, and they lower your cost per kilogram. At 12 in across, they need an external or floor-standing spool holder.
How Many Grams Are in a Roll of Filament?
A standard roll of 3D printer filament holds 1 kg (1,000 grams) of filament. That's the net weight of the plastic only and doesn't include the spool. Other common sizes across the industry include 250 g and 500 g spools for specialty materials, and 2–5 kg spools for high-volume printing.
At Atomic, every full-size spool contains 1 kg or 3.5 kg of filament, and every sample coil contains 50 g.
How Big Are Atomic Sample Coils?
Each Atomic sample coil contains 50 grams of 1.75 mm filament. It's the same filament we put on our full-size spools, wound into a small coil. That works out to roughly:
- PLA: about 17 m (55 ft)
- PETG / PCTG: about 16–17 m (54–55 ft)
That's enough for a color test, a calibration print or a small part, so you can check the color, finish and print settings before buying a full 1 kg spool.
Browse our sample coils and sample packs.
How Much Filament Is Left on My Spool?
Weigh the spool on a kitchen or postal scale and subtract the empty spool weight:
- 1 kg Atomic spool: filament left = scale reading − 260 g
- 3.5 kg Atomic spool: filament left = scale reading − 936 g
Example: a 1 kg Atomic spool that weighs 560 g on the scale has about 300 g of filament left, enough for a medium-sized print. Compare that to the filament weight your slicer shows before you start a long print.
How Many Meters of Filament Are on a 1 kg Spool?
The length depends on the plastic's density and the filament diameter. Approximate lengths for a 1 kg spool:
| Material | 1.75 mm | 2.85 mm |
|---|---|---|
| PLA | ~335 m (1,100 ft) | ~126 m (415 ft) |
| PETG | ~327 m (1,075 ft) | ~123 m (405 ft) |
| PCTG | ~338 m (1,110 ft) | ~127 m (418 ft) |
| ABS | ~400 m (1,310 ft) | ~151 m (495 ft) |
| ASA | ~389 m (1,275 ft) | ~146 m (480 ft) |
A 3.5 kg spool holds 3.5 times these lengths. For example, a 3.5 kg spool of 1.75 mm PLA holds roughly 1,170 m (3,850 ft).
Spool Size vs Filament Diameter
These two get mixed up a lot:
- Spool diameter is how big the spool is across: 7 7/8 in (200 mm) for our 1 kg spools and 12 in (305 mm) for our 3.5 kg spools. It matters for fitting your spool holder or AMS.
- Filament diameter is the thickness of the plastic strand: 1.75 mm or 2.85 mm. It has to match your printer. Most modern printers, including Bambu Lab, Prusa and Creality, use 1.75 mm. Some printers, such as many Ultimaker models, use 2.85 mm.
Atomic filament is held to ±0.02 mm in diameter and roundness, checked with multi-axis laser micrometers during extrusion. Shop 2.85 mm filament.
Spool Size FAQ
What size is a standard 1 kg filament spool?
Most 1 kg spools are roughly 200 mm (about 8 in) across and 55–70 mm wide, though it varies by brand. Atomic 1 kg spools are 7 7/8 in (200 mm) across and 2 5/8 in (67 mm) wide, with a 2 in (51 mm) center hole.
How much does an empty filament spool weigh?
Empty plastic spools usually weigh 150–300 g, depending on the brand. An empty Atomic 1 kg spool weighs 260 g, and an empty 3.5 kg spool weighs 936 g.
Will Atomic spools fit in the Bambu Lab AMS?
Yes. Every 1 kg Atomic spool is designed to fit and feed in the Bambu AMS. See the full list of AMS-compatible products.
Will the 3.5 kg spool fit my printer?
The 3.5 kg spool is 12 in across, which is too large for the AMS and most built-in spool holders. Use an external or floor-standing spool holder with a hub that fits a 2 in center hole.
What are Atomic spools made of? Can I recycle them?
Our spools are ABS plastic. You can send clean empty spools back through our Spool Recycling Program for $2 store credit per 1 kg AMS-compatible spool and $3 per 3.5 kg spool. We reuse them. You can also recycle them wherever ABS is accepted.
How much filament is in an Atomic sample coil?
50 grams of 1.75 mm filament, which is about 16–17 meters. It's enough for a color test, a calibration cube or a small part.
How long does a 1 kg spool of filament last?
It depends on what you print. A typical small figure or bracket uses 10–50 g, so a 1 kg spool covers anywhere from a handful of large prints to dozens of small ones. Your slicer shows the grams for each print before you start.