Volumetric Let-Down Ratio Calculator

Volumetric Let-Down Ratio Calculator

Convert target weight percentages to volumetric feeder settings using material densities

Base Resin
Additives — Target Weight Percentages
Additive 1
How it works:
  • Volumetric LDR is the volume ratio your feeder needs to achieve the target weight percentage. A denser additive needs fewer pellets by volume to hit the same weight target.
  • 1:N notation: Set your volumetric feeder to dispense 1 part additive for every N parts base resin.
  • Densities shown are typical bulk pellet values. Actual bulk density depends on pellet shape, size, and packing. Calibrate your feeder with actual materials.
  • For weight-based BOM from let-down ratios, use our Resin Mix BOM Calculator.

Learn more: Injection Molding Guide · Blow Molding Guide