Coating Coverage from Volume-Solids and DFT
Theoretical and practical coverage, gallons.
Example
You enter
- Volume solids (%, from the data sheet) 60
- Target dry-film thickness (mils) 5
- Area to coat (ft²) 2000
- Application loss (%, spray ~35) 35
You get
- Theoretical coverage 192.5 ft^2/gal
- Practical coverage (after loss) 125.1 ft^2/gal
- Gallons required 16.0 gal
- Wet-film thickness to read 8.33 mils
Checked against published worked examples from: SSPC / AMPP PA 2.
Details, formula, and sources
ScopeTheoretical and practical coverage, gallons, and the wet-film thickness from a coating's volume-solids and a target dry-film thickness (SSPC/AMPP PA 2; 1604 constant).
Formula or tabletheoretical = 1604 x (vol_solids/100) / dft; practical = theoretical x (1 - loss/100); gallons = area / practical; wft = dft / (vol_solids/100).
Source and editionSSPC / AMPP PA 2 (dry-film thickness) and the 1604 ft^2-mil/gal coverage constant by name; first-principles film-build math.
Free accessThe 1604 coverage constant is public arithmetic (231 in^3 per gallon / 0.144 in^3 per ft^2-mil = 1604.2, rounded). SSPC / AMPP PA 2 is a published consensus standard.
What governsEstimate. AHJ and licensed professional govern.
API field namesvol_solids_pct, dft_mils, area_ft2, loss_pct, theoretical_cov_ft2_gal, practical_cov_ft2_gal, gallons, wft_mils
- Coverage constant 1604 ft^2-mil per gallon at 100% volume solids (231 / 0.144 = 1604.2, rounded)physical fact
- Application loss 35% spray-loss default (varies with method and conditions)coatings practice