Infill Calculator
Calculate optimal infill percentage from use case and required strength.
Compares grid, gyroid, honeycomb, and cubic patterns for PLA, PETG, and ABS.
3D print infill percentage determines the internal density of a printed part — the lattice structure inside the solid outer walls. Infill directly controls print strength, weight, material usage, and print time.
Material volume formula: Internal Volume = Part Volume × (1 − Shell Fraction) × (Infill % ÷ 100)
Total material used: Total Volume = Shell Volume + Internal Volume Filament Length = Total Volume ÷ (π × (Filament Diameter ÷ 2)²)
Where:
- Part Volume: total geometric volume of the model in mm³
- Shell Fraction: proportion occupied by perimeter walls; 3 walls × 0.4mm each = 1.2mm, typically 10–30% of volume depending on part size
- Infill %: percentage of interior space filled; 0% is hollow (shell only), 100% is completely solid
- Filament Diameter: 1.75mm or 2.85mm; the formula converts volume to filament length for cost estimation
Infill patterns and their strength characteristics:
- Grid/Rectilinear (0°/90°): Fast, decent strength in XY, weak in Z
- Gyroid: Excellent isotropic strength in all directions, good for flexible parts
- Honeycomb: Strong, moderate speed, visually appealing
- Lightning: Fastest, minimal material, supports top surfaces only, not structural
- Cubic/3D Honeycomb: Strong in all 3 axes; recommended for structural parts
Reference: infill percentage guidelines:
- 0–5%: Decorative only (vases, figurines, no load)
- 10–20%: Light-duty parts, enclosures, prototypes
- 20–40%: General purpose: most everyday prints
- 40–60%: Mechanical parts with moderate stress
- 60–80%: High-stress functional parts
- 80–100%: Maximum strength; rarely needed above 60% with good pattern choice
Worked example: Part volume: 45,000 mm³. Gyroid infill at 30%. 3 perimeters at 0.4mm = shell ~20% of volume.
- Shell volume = 45,000 × 0.20 = 9,000 mm³
- Internal volume available = 45,000 − 9,000 = 36,000 mm³
- Infill material = 36,000 × 0.30 = 10,800 mm³
- Total material = 9,000 + 10,800 = 19,800 mm³
Increasing infill from 30% to 60% adds only 10,800 mm³ more material (≈ 28g more PLA at 1.24 g/cm³) but roughly doubles the part’s compression strength.