Purge Tower Filament Waste Calculator
Calculate total filament waste from a multi-material purge tower.
Enter purge volume per color change, number of changes, and filament price for waste cost.
Multi-material printing systems (Bambu AMS, Prusa MMU, ERCF/Happy Hare) purge the previous filament color before printing with the next. The purge volume — how many cubic millimeters of new filament to push through the nozzle until the old color is fully cleared — directly determines how much material is wasted in the purge tower.
Typical purge volumes. For a standard 0.4 mm nozzle, a good starting point is 100-200 mm³ per color change for same-family filaments and 300-500 mm³ when switching between very different colors (white to black being the worst case) or between transparent and opaque materials.
The default Bambu AMS flush volume is around 450 mm³ per change (before their adaptive purge optimizations). Custom profiles tuned for specific color pairs can reduce this to 80-150 mm³ with careful calibration.
Converting mm³ to grams. Filament density varies by material:
- PLA: 1.24 g/cm³
- PETG: 1.27 g/cm³
- ABS: 1.05 g/cm³
- TPU: 1.20 g/cm³
mass (g) = volume (mm³) x density (g/cm³) / 1000
Reducing waste. The most effective strategies are: calibrating exact flush volumes for your specific color pairs, using the “purge into infill” option (Bambu/OrcaSlicer), and printing infill-adjacent purge objects rather than a standalone tower. Some systems support “tip shaping” to reduce the mixing zone length.
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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