How this filament cost calculator works
Filament cost is fundamentally a weight problem. The core formula is simple:
Print material cost = Grams used × Cost per gram
But real prints rarely use exactly what the slicer predicts. You lose filament to purge lines, priming, skirts, brims, supports, and failed prints. This calculator lets you apply a configurable waste percentage so your estimate reflects your actual workflow instead of a universal guess.
The effective cost per gram is the cost per gram after accounting for waste — it is always slightly higher than the raw cost per gram. The prints per spool figure uses whole prints, because you can't print half a print and still call it a success. The remaining filament shows what's left on the spool after your planned prints.
Key terms explained
- • Spool weight — the net filament weight, usually 250 g, 500 g, 1 kg, or 2–5 kg for bulk spools.
- • Empty spool weight — tare weight of the bare spool. Useful if you weigh a partially used spool and subtract it.
- • Usable filament — the filament you can actually print with. Some stays on the spool or gets tangled; assume 95–98% usable in practice.
- • Supports — extra material for overhangs. Can add 5–30% to a print's weight depending on geometry.
- • Infill — internal structure. 10–20% is common; higher infill means more grams and more cost.
- • Purge — filament wasted when switching colors or materials on multi-material systems.
- • Waste % — your catch-all for skirts, brims, priming, failed prints, and slicer underestimation.
- • Slicer estimate — the grams your slicer predicts. Treat it as a baseline, then add waste.
Material notes: PLA, PETG, ABS, TPU
Density ≈ 1.24 g/cm³. Cheapest and easiest. Low warp, low waste. Great for prototypes and display models.
Density ≈ 1.27 g/cm³. Tougher, slightly more stringy. Supports can be harder to remove, so waste may be higher.
Density ≈ 1.04 g/cm³. Warps easily; failed prints are common without an enclosure. Budget a higher waste %.
Density ≈ 1.21 g/cm³. Flexible, slow to print, and can be tricky to feed. Waste from failed feeds is common.