How do you calculate infill material weight?

Multiply internal part volume by infill percentage and material density to get base mass, then apply a pattern multiplier. With 85 cm³ at 35% infill, 1.24 g/cm³ density and a 1.05x multiplier, base mass is 3,689 g and estimated infill material is 3,873.45 g.

Why is my infill heavier than the infill percentage suggests?

Slicer patterns lay down extra material at junctions and the slicer rounds up partial cells, so a 35% setting rarely yields exactly 35% by mass. The pattern multiplier (1.05x in the default) captures that overhead; gyroid and cubic patterns typically run 1.03x to 1.10x.

What is a good infill percentage for strength versus material use?

For cosmetic or low-load prototypes 10-20% is plenty; functional parts usually run 30-50%; load-bearing brackets and jigs sit at 50-80%. Above 60% the strength gain per gram drops sharply, so going solid is rarely worth the material.

Does infill pattern change material consumption?

Yes. At equal density, lines and grid are leanest, gyroid and cubic add a few percent for their 3D structure, and honeycomb is heavier still. The multiplier lets you bias the estimate to match your chosen pattern.

How do I convert infill grams to filament length or cost?

Divide grams by spool price-per-gram for cost, or by the filament's linear density (about 3 g per meter for 1.75 mm PLA) for length. The 3,873.45 g result is roughly 3.9 kg, just under four standard 1 kg spools.

Infill density vs wall count for strength?

Below 50% infill, adding perimeters usually buys more strength per gram than raising infill, because load travels through the shell first. Use this calculator alongside a wall-volume estimate to balance the two.

Additive Manufacturing calculator

Infill Material Calculator

Infill material is the mass of filament, powder, or resin deposited inside a part's solid envelope to give it stiffness without printing it solid. Print engineers, additive estimators, and shop owners use it to forecast spool consumption and material cost before a job ever reaches the bed. Because infill often accounts for the majority of a part's mass at densities above 25%, getting this estimate right is the difference between a quote that holds margin and one that bleeds it. The pattern multiplier matters because gyroid, cubic, and honeycomb patterns each extrude slightly more material than the raw geometric infill share suggests.

What this calculator does

Estimate FDM infill material from solid part volume, infill percentage, material density, and pattern multiplier.
a designer or FDM estimator needs to compare infill settings before slicing or quoting a part
It computes infill mass in grams from internal volume, infill density percentage, material density, and a pattern correction multiplier.

Formula used

Base infill material = internal part volume × infill percentage × material density
Estimated infill material = base material × pattern multiplier

Inputs explained

Internal part volume:
Infill percentage:
Material density:
Pattern multiplier:

How to use the result

Use it when quoting a print, ordering filament for a batch, or comparing how a change in infill density or pattern affects material cost.
It models only the infill volume you supply — it excludes perimeters, top and bottom solid layers, and support structures, so for thin-walled parts the shells can dominate and this estimate understates total mass.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 22,301 printing and related support establishments employing about 386,248 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate infill material weight? Multiply internal part volume by infill percentage and material density to get base mass, then apply a pattern multiplier. With 85 cm³ at 35% infill, 1.24 g/cm³ density and a 1.05x multiplier, base mass is 3,689 g and estimated infill material is 3,873.45 g.
Why is my infill heavier than the infill percentage suggests? Slicer patterns lay down extra material at junctions and the slicer rounds up partial cells, so a 35% setting rarely yields exactly 35% by mass. The pattern multiplier (1.05x in the default) captures that overhead; gyroid and cubic patterns typically run 1.03x to 1.10x.
What is a good infill percentage for strength versus material use? For cosmetic or low-load prototypes 10-20% is plenty; functional parts usually run 30-50%; load-bearing brackets and jigs sit at 50-80%. Above 60% the strength gain per gram drops sharply, so going solid is rarely worth the material.
Does infill pattern change material consumption? Yes. At equal density, lines and grid are leanest, gyroid and cubic add a few percent for their 3D structure, and honeycomb is heavier still. The multiplier lets you bias the estimate to match your chosen pattern.
How do I convert infill grams to filament length or cost? Divide grams by spool price-per-gram for cost, or by the filament's linear density (about 3 g per meter for 1.75 mm PLA) for length. The 3,873.45 g result is roughly 3.9 kg, just under four standard 1 kg spools.

Last reviewed 2026-05-12.