Formulas, conversions and equations for Wet Film Thickness, Dry Film Thickness and Coating Coverage
Easily convert and calculate dry and wet film thicknesses and coverage of coatings applied to substrates. Typically the volume percent solids in the coating will be known. Check the paint's directions for use or "Material Safety Data Sheet" (MSDS).
"Wet Film Thickness" (WFT) = W (can be known, specified or calculated)
"Dry Film Thickness" (DFT) = D (can be known, specified or calculated)
Volume percent solids in paint = P (this can be known, specified or calculated) Volume percent of reducing agent (added to paint) = R
Note that P&R should be expressed as a decimal less than 1. eg 72% is 0.72
Thickness calculation:
No reducing agent or thinner added to the paint:
If reducing agents or thinners are added to the paint:
Coverage Calculation:
From the above formula, the wet film thickness (WFT) can be easily calculated for a given dry film thickness (DFT). If the wet film thickness is known, the coating coverage in square feet per gallon can be calculated using the following formula:
Coverage in "square feet per gallon" = 1604.17 divided by "Wet Film Thickness" in MILS
(**Above formula is based on a gallon with a volume of 231 cubic inches)
Example: If "wet film thickness is 10 mils (0.010")
Coverage is: 1604.17 divided by 10, or 160.417 square feet per gallon.
