How is the shell volume calculated?

The bounding box surface area is estimated from the length, width, and height you enter, then multiplied by the wall thickness (wall count times line width) for the vertical shell and by the top/bottom thickness (layer count times layer height) for the horizontal shell. This is an approximation based on a box shape, not the exact geometry of your model.

Why do you ask for both model volume and bounding box dimensions?

Model volume gives the true solid volume of the part, which most slicers report directly. Bounding box dimensions approximate the outer surface area needed to estimate shell thickness. Irregular shapes will have somewhat more or less surface area than a plain box, so the shell estimate is approximate.

What happens if the shell volume is larger than the model volume?

The calculator caps the shell volume at the total model volume and shows a note. This can happen with very thin or small parts where the walls and top/bottom layers would occupy the entire model, meaning the part is effectively solid regardless of the infill percentage.

How accurate is this compared to my slicer?

Expect a rough estimate, often within 10 to 20 percent of the slicer value, since real slicers trace the actual model geometry rather than a bounding box. Use this tool for quick planning, not as a replacement for slicing the actual file.

What are typical wall count and line width values?

Most prints use 2 to 4 walls with a line width of 0.4 to 0.45 mm for a 0.4 mm nozzle. Top/bottom layers commonly range from 3 to 6, and layer height is typically 0.12 to 0.28 mm depending on print quality settings.

What is the density of common filaments?

PLA is about 1.24 g/cm3, ABS about 1.04 g/cm3, PETG about 1.27 g/cm3, TPU about 1.21 g/cm3, Nylon about 1.14 g/cm3, and ASA about 1.07 g/cm3. Pick your material or enter the density from your filament manufacturer if it differs.

Infill Weight Calculator

Enter model volume, bounding box dimensions, infill percentage, wall count, and layer settings to estimate total filament weight.

Model & Print Settings

Model Volume (cm³)

Found in your slicer's print statistics panel.

Bounding Box Dimensions (mm)

Used to approximate shell surface area. Real geometry may differ from a plain box.

Infill Percentage: 20%

0% 100%

Wall Count

Line Width (mm)

Top/Bottom Layers

Layer Height (mm)

Filament Material

Enter model volume and bounding box dimensions to see the weight estimate.

Estimated Filament Weight

0.0 g

shell + infill

Shell Volume

0.00 cm³

Infill Volume

0.00 cm³

Item	Value

Summary

This calculator estimates the total filament weight of a 3D print by splitting the model into a shell (walls plus top/bottom solid layers) and an infilled interior. Enter the model volume and bounding box dimensions from your slicer, then set infill percentage, wall count, line width, top/bottom layer count, and layer height to get a weight estimate in grams. The shell volume is approximated from the bounding box surface area, so treat the result as a planning estimate rather than exact slicer output.

How it works

Enter the model volume in cubic centimeters, shown in your slicer print statistics.
Enter the bounding box length, width, and height in millimeters, also shown by most slicers.
Set the infill percentage and the number of perimeter walls.
Enter line width and layer height, then the number of solid top/bottom layers.
Choose a filament material or enter a custom density.
Read the estimated filament weight and the shell/infill volume breakdown.

Use cases

Estimating filament weight before starting a print with a specific infill setting.
Comparing how wall count or infill percentage changes total weight.
Checking whether a print will fit on a partially used spool.
Planning material budgets for prints with heavier wall or top/bottom settings.
Sanity-checking a slicer weight estimate against a rough manual calculation.
Understanding how much of a print weight comes from shell versus infill.

Frequently Asked Questions

Last updated: 2026-09-09 · Reviewed by Nham Vu