Multicolor purge waste calculator
How much filament your color changes flush away, what it costs per item, and how much you save by putting more items on each plate.
Working it out…
How this is worked out
Each time the printer swaps color it pushes the old color out of the nozzle until the new one runs clean. That purged filament, and any prime tower, is bought and thrown away, and it is the same whether the plate holds one item or eight.
Purge per plate = color changes × flush volume (mm³) × density (g/cm³) ÷ 1000
or, from the slicer, the flushed grams it reports
Waste per plate = purge + prime tower
Waste per item = waste per plate ÷ items on the plate
Waste cost per item = waste per item ÷ 1000 × filament price per kg
Share wasted = waste per item ÷ (waste per item + filament in the item)
Assumptions
- Every color change flushes the same volume. Slicers use a larger flush for dark-to-light changes than for light-to-dark ones; if your plate mixes them, use the slicer total instead.
- Items on one plate share the same color changes. That holds when they change color at the same heights, which is the usual case for copies of one model.
- Filament cut off and wasted when the printer swaps spools is not counted, because it differs between machines.
- Density turns volume into weight. The presets are from the makers' data sheets; other brands and colors differ a little.
- The starting values for color changes, flush volume, tower and filament price are examples, not measurements.
To charge for the waste, add the waste per item to the filament grams in the 3D print price calculator.
Preset figures and where they come from
Each figure was read on the company’s own page, checked on 15 November 2026.
| Preset | Figure | Source |
|---|---|---|
| Bambu Lab PLA Basic | 1.24 g/cm³ | cdn.shopify.com |
| Polymaker PolyTerra PLA | 1.31 g/cm³ | polymaker.com |
| Polymaker PolyLite PLA | 1.17 g/cm³ | wiki.polymaker.com |
Every preset is only a starting value. Change any field if your account, country or plan differs.
Questions sellers ask
How much filament does an AMS waste per print?
It depends almost entirely on how many color changes the plate has. With the example figures here, 50 changes at 250 mm³ of PLA flush 15.5 g, and an 8 g prime tower brings it to 23.5 g, more than half the weight of a 40 g item. A two-color sign that changes color once is close to nothing; a multicolor figure with a change on every layer can waste more than the model weighs.
How can I cut purge waste?
The biggest saving is to print several copies on one plate, because they share the same color changes: four items instead of one cuts the waste per item to a quarter. Beyond that, design so colors change at fewer heights, order the colors so the slicer can use smaller flush volumes, and use the slicer options that flush into the model’s infill or into a support instead of the purge chute.
Where do I find the flush volume?
In Bambu Studio and OrcaSlicer, the flushing volumes table is opened from the filament list and gives a volume in mm³ for each pair of colors. After slicing, the plate summary shows the total flushed filament in grams, which you can enter directly using "From my slicer total".
Should I charge customers for purge waste?
Yes. The customer’s item could not be made without it, so it is a material cost like any other. Add the waste per item to the filament used in your pricing, and quote multicolor items with few copies per plate higher than batch orders.