Coatings, Inks & Specialty Chemical Production calculator

Letdown Ratio Calculator

Express your letdown as pounds of vehicle per pound of mill base. Enter both net charge weights from the same batch ticket.

What this calculator does

  • Calculate the vehicle-to-mill-base mass ratio and the resulting blend composition.

Formula used

  • Vehicle:mill-base ratio = vehicle mass ÷ mill-base mass
  • Blend mass = vehicle mass + mill-base mass
  • Mill-base weight share = mill-base mass ÷ blend mass × 100

Inputs explained

  • Letdown Vehicle Mass: Net vehicle weight from the letdown batch ticket.
  • Mill-Base Mass: Net concentrate weight charged before letdown.

How to use the result

  • Best suited to concentrate letdown ticket review, vehicle charge comparison.
  • This ratio does not establish pigment concentration, compatibility, or final viscosity.

Current U.S. benchmarks

  • Industrial electricity averages 9.77 cents per kWh across the U.S. (EIA, Jul 2026), up 4.7% from a year earlier. Energy-intensive steps carry this directly into unit cost.
  • The producer price index for industrial chemicals stands at 336.006 (BLS, Aug 2026), up 13.3% from a year earlier. Quotes priced off last quarter's material cost miss this move.
  • The U.S. has 14,543 chemical manufacturing establishments employing about 911,245 workers (Census County Business Patterns, 2023).

Common questions

  • What does a 3:1 letdown ratio mean? It means three pounds of vehicle per pound of mill base. Mill base represents 25% of the combined mass before other additions.
  • Can I enter gallons instead of pounds? No. Convert each component volume using its own density, or weigh both charges. Different densities change a volume ratio into a different mass ratio.
  • Does vehicle mean only solvent? No. Use the complete letdown vehicle specified on the batch ticket, which may include resin, solvent, water, or other ingredients.
  • Does the result predict final color strength? No. Color strength also depends on pigment content and dispersion. Use qualified drawdowns or color measurements to approve the letdown.

Last reviewed 2026-10-01.