Infill Weight & Cost Calculator

Estimate the filament weight, length, and cost a print uses at a given infill percentage.

Model & Infill

Solid volume (cm³)

Infill (%)

Solid allowance (cm³)Perimeters + top/bottom, counted as 100% solid

Material & Price

Density (g/cm³)

Price per kg

Typical densities: PLA 1.24, PETG 1.27, ABS 1.04, ASA 1.07, Nylon 1.14, TPU 1.21, PC 1.20 g/cm³.

Estimated Filament

Total weight

5.0 g

Filament length1.66 m

Estimated cost0.12

Infill contribution5.0 g

Solid allowance0.0 g

Estimate only. This covers the infill plus any solid allowance you enter. Real prints also spend filament on perimeters, top/bottom layers, supports, and purge. For an exact figure, slice the model.

How infill drives weight and cost

Infill is the internal lattice that fills the hollow inside of a print. At 20% infill, roughly a fifth of the model's interior volume is plastic and the rest is air, so infill percentage scales almost linearly with how much filament the inside of a part consumes.

This tool works from three quantities:

Infill mass = solid volume × infill% × density. A 20 cm³ model at 20% in PLA (1.24 g/cm³) is about 5 grams of infill.
Solid allowance = the volume of walls and top/bottom layers, counted as 100% solid, so you can fold the shell back into the estimate.
Cost = total weight ÷ 1000 × your price per kilogram.

Length assumes standard 1.75mm filament, whose cross-section is about 2.405 mm². Weight is converted to volume via density, then divided by that area to get length.

Reading the numbers honestly

Treat this as an estimate of the infill contribution plus whatever solid allowance you enter, not a full print total. A real print also lays down perimeters, solid top and bottom layers, supports, and a purge line, and those are often a large share of a small or low-infill part.

That means low-infill estimates tend to understate total filament use, because the fixed shell cost dominates. For a final, exact number, slice the actual model and use your slicer's own filament estimate.

Need related numbers? Convert between weight and spool length with the filament length & weight converter, or work out full job pricing with the 3D print cost calculator.

Tips & Best Practices

Use your slicer for finals

For quotes and inventory planning, trust the slicer's gram and length estimate, which accounts for walls, top/bottom layers, and supports that this calculator only approximates via the solid allowance field.

Match the density

Density varies by material and even by brand. PLA is about 1.24 g/cm³, PETG 1.27, ABS 1.04. Using the wrong density scales both weight and cost proportionally, so set it before trusting the output.

Infill is not linear at the shell

Dropping from 20% to 10% infill roughly halves the infill mass, but the perimeters and top/bottom layers stay the same. On thin-walled parts the shell can outweigh the infill entirely.

Estimate the solid allowance

If you want a closer total, add a rough wall-and-surface volume in the solid allowance field. Even a ballpark figure pulls low-infill estimates much closer to reality.

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