3D Printing Filament Cost Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/8/2026
The filament mass needed is calculated by treating the filament as a cylinder: volume = π × radius² × length, then mass = volume × material density. For 10 m of 1.75 mm PLA, that's about 29.8 g, or €0.60 with a €20-per-1,000 g spool.
Explanation
Most slicer software (Cura, PrusaSlicer, or Bambu Studio) shows the filament length needed for a print, but rarely its direct cost. This calculator fills that gap: since the filament is a cylinder of constant cross-section, its volume is calculated with π × radius² × length, then its mass by multiplying that volume by the material's density — a figure that varies by filament type (PLA, PETG, and ABS do not have the same density, so not the same mass for the same volume). The final cost is obtained by relating this mass to the price of the spool used. This estimate is useful for comparing the real cost of several parts before printing, budgeting a project requiring multiple spools, or simply understanding why two parts of the same apparent volume (but different materials) don't cost the same. For hollow parts or those with partial infill, the length shown by the slicer already accounts for this reduced fill — so there is nothing extra to correct here, unlike a solid-volume calculation such as our cylinder volume calculator.
Example: a PLA part requiring 10 m of filament
Inputs
Length: 10 m. Diameter: 1.75 mm. Material: PLA (density 1.24 g/cm³). Spool: €20 for 1,000 g.
Calculation
Radius = 1.75 ÷ 2 ÷ 10 = 0.0875 cm. Volume = π × 0.0875² × 1,000 cm ≈ 24.05 cm³. Mass = 24.05 × 1.24 ≈ 29.83 g. Cost = (20 ÷ 1,000) × 29.83 ≈ €0.60.
Result
This part uses about 29.8 g of PLA filament, for a material cost of about €0.60.
Frequently asked questions
Why don't PLA, PETG, and ABS cost the same for the same length?
Their densities differ (about 1.24 g/cm³ for PLA, 1.27 for PETG, 1.04 for ABS): for the same volume, ABS is therefore slightly lighter than PLA or PETG, which directly affects the mass and thus the cost, even for the same filament length. Our percentage calculator lets you express this difference directly as a percentage between two quotes for different materials.
Does this calculation account for the part's infill?
Yes, indirectly: the filament length you enter here is the one already calculated by your slicer, which accounts for the chosen infill percentage, walls, and any supports. This calculator only converts that length into mass and then cost, without redoing this internal volume calculation.
Does the calculation change with 2.85 mm filament?
Yes: for the same length, 2.85 mm filament contains much more material than 1.75 mm filament (volume depends on the square of the radius), so a noticeably higher mass and cost. This calculator's diameter selector automatically applies this difference.