How does infill percentage affect material weight?

Infill percentage controls the density of the internal structure. At 0% infill, the part is hollow (only shells). At 100%, it is solid throughout. The relationship is approximately linear for the interior volume: doubling infill roughly doubles the infill material used, while the shell weight stays constant. For most functional parts, 15–25% infill provides adequate strength at a significant material saving.

What is the difference between shell weight and infill weight?

Shell weight is the material used for the outer perimeter walls and top/bottom solid layers — this is always fully solid regardless of infill setting. Infill weight is the material used inside the part at your chosen infill density. For small parts with thin walls, the shell can account for 50–80% of total weight.

How do I find my part dimensions?

Enter the bounding-box length, width and height (X, Y, Z) of the part in millimetres. Every slicer shows these: in PrusaSlicer and Bambu Studio the object size appears in the right-hand object/manipulation panel; in Cura it is in the Scale tool and the object list. You can also read them straight from your CAD software (Fusion 360: Inspect > Measure or the bounding-box dimensions; Blender: the Item panel, N key). Using real dimensions — rather than a single volume figure — is what lets the calculator separate the solid shell from the infilled interior correctly.

How accurate is the print time estimate?

The print time estimate is a rough guide based on the volumetric-flow model: time ≈ extruded volume ÷ (print speed × layer height × line width), with a 0.5 duty factor to allow for travel moves, acceleration, retraction and cooling. Slicer software is far more accurate because it simulates every move, per-feature speeds, fan delays and layer transitions, so use your slicer's figure for planning. This calculator is best for quick comparisons between different infill settings on the same part.

Which infill percentage should I use?

General decorative prints: 10–15%. Standard functional parts: 20–30%. High-strength mechanical parts: 40–60%. Parts under significant load or impact: 60–80%. Solid (100%) is rarely needed — a well-designed part at 40% infill with 3–4 perimeters is usually stronger than 100% infill with fewer walls, because perimeter walls contribute more to tensile strength.

Infill Weight Calculator — Material Weight & Filament Length by Infill %

Infill Weight Calculator — Material Weight & Filament Length by Infill

Calculate print weight, shell weight, infill weight, filament length and estimated print time from your part's dimensions, infill percentage, wall thickness and material type.

Length

Bounding-box length (X) of the part from your slicer or CAD

Width

Bounding-box width (Y) of the part

Height

Bounding-box height (Z) of the part — real dimensions let us split shell from infill accurately

Infill Percentage

Percentage of solid fill inside the part — 15–25% is typical for functional parts

MaterialMaterial density affects weight and filament length

Wall Thickness

Total perimeter wall thickness (e.g. 3 walls × 0.4mm nozzle = 1.2mm)

Top / Bottom Layers

Number of solid layers on top and bottom surfaces

How We Calculate This

This calculator works from your part's real bounding-box dimensions (length × width × height). It derives the solid perimeter walls and top/bottom layers from actual geometry, applies your infill density only to the remaining interior, then converts the used volume to weight, filament length and an estimated print time.

Formulae

Solid volume = Length × Width × Height
Wall volume = (L × W − (L − 2t)(W − 2t)) × H, where t = wall thickness
Top/bottom volume = inner cross-section × (top/bottom layers × layer height × 2 faces)
Shell volume = Wall volume + Top/bottom volume
Infill volume = (Solid volume − Shell volume) × (Infill % / 100)
Total weight = (Shell volume + Infill volume) × Material density
Filament length = Used volume / Filament cross-section area (π r²)
Print time ≈ Used volume / (Print speed × Layer height × Line width × 0.5 duty factor), where line width ≈ nozzle × 1.1

Frequently Asked Questions

Last updated: March 2026

All calculations are estimates. Always verify settings with test prints before committing to final prints.

Infill Weight Calculator — Material Weight & Filament Length by Infill

How We Calculate This

Formulae

Frequently Asked Questions

Related Calculators

Layer Height Calculator

Print Speed Calculator

Infill Calculator

Wall Thickness Calculator

Print Time Estimator