Calculate PLA weight in grams from model volume and infill, or convert filament length to weight and back, using typical PLA densities and optional cost.

Approximate shell = surface area ร— thickness, capped at model volume. Blank surface area uses an equal-volume cube; a slicer gives a better estimate.

Optional settings

PLA Weight Formulas

The following formulas calculate solid PLA mass from simple shape dimensions (mass = volume ร— density). Hollow dimensions must be positive and fit inside the outer dimensions; wall, web and flange thicknesses must describe a valid cross-section. For a printed part, the calculator separately estimates the shell and infill. Its surface-area ร— wall-thickness shell model is a rough approximation, not a slicer toolpath calculation.

PLA Flat Sheet Weight Formula = L * W * H * d

PLA Round Bar Weight Formula = ฯ€ * (D2 / 4) * L * d

PLA Square Hollow Tube Weight Formula = [W2 – (W – 2T)2] * L * d

PLA Round Hollow Tube Weight Formula = ฯ€ * (R2 – r2) * L * d

PLA Square Angle Weight Formula = (2*W*T – T2) * L * d

PLA T bar Weight Formula (uniform thickness) = (W*T + (H – T)*T) * L * d

PLA C Channel Weight Formula = [2*W*T1 + (H – 2*T1)*T2] * L * d

Variables used in these equations: 

  • L is the length
  • W is the width (or outer width / flange width, depending on shape)
  • H is the height (or thickness, for a flat sheet)
  • d is the density
  • D is the outer diameter
  • T is the thickness (wall/leg thickness; for the T bar formula it is assumed the flange and web have the same thickness)
  • R is the outer radius
  • r is the inner radius
  • T1 is the flange thickness (C channel)
  • T2 is the web thickness (C channel)

Use consistent units. For example, if lengths are in cm and density is in g/cmยณ, the resulting weight is in grams. If lengths are in inches, use density in lb/inยณ to get pounds.

What is the density of PLA?

PLA density depends on the exact product and formulation. Use the density stated by your filament manufacturer or a measured value. The calculatorโ€™s identified product presets are examples, not universal values for PLA+, silk, matte or filled PLA. A density of 1.24 g/cmยณ corresponds to approximately 0.0448 lb/inยณ. Manufacturer density, diameter tolerance, actual shell/top/bottom geometry, supports, flow and waste all affect consumption; verify with your slicer and actual print.