How do you calculate coating volume for a target film?

Multiply area by dry mils by 0.000623, then divide by transfer efficiency and by volume solids. The example's 500 ft² at 2 mils is 0.779 gallons at 80% efficiency.

Where does the 1,604 figure come from?

One US gallon spread 1 mil thick covers 1,604 ft². It prices pure coating solids, so real products cover less by their volume solids share.

Why does volume solids change the gallons so much?

Only the solids stay on the part; the solvent leaves. A 60% solids enamel delivers 0.6 gallons of film per liquid gallon, so the requirement rises by two-thirds.

Is this the right page for powder coating?

No. Powder build runs on pounds and specific gravity, not liquid gallons. The powder coverage page on this hub is the powder twin of this calculation.

Finishing calculator

Film Thickness Calculator

Size the liquid a target film consumes. Enter the coated area, the dry film build, transfer efficiency and volume solids.

What this calculator does

Convert an area and a target dry film into the liquid gallons a sprayer must consume, through transfer efficiency and volume solids.

Formula used

Theoretical solids volume = area × dry mils × 0.000623
Coating volume required = theoretical volume ÷ transfer efficiency ÷ volume solids
Wet film needed = dry mils ÷ volume solids
Gallons per 1,000 ft² = volume required ÷ area × 1,000

Inputs explained

Coated Surface Area: Area the specified film must cover: part area × part count.
Target Dry Film Build: The specified cured thickness; volume scales linearly with it.
Transfer Efficiency: Share of sprayed material landing on the part for this applicator.
Volume Solids: The data sheet's volume solids; the constant assumes 100%.

How to use the result

Best suited to estimating material for an area-and-build job, bracketing best-case material against a bid, pricing an applicator upgrade by efficiency.
Thinning at the gun dilutes solids and raises the liquid requirement. Mix, purge and pot-life waste sit on the material coverage page. The page sizes volume; dry-film gauging accepts the work.

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

How do you calculate coating volume for a target film? Multiply area by dry mils by 0.000623, then divide by transfer efficiency and by volume solids. The example's 500 ft² at 2 mils is 0.779 gallons at 80% efficiency.
Where does the 1,604 figure come from? One US gallon spread 1 mil thick covers 1,604 ft². It prices pure coating solids, so real products cover less by their volume solids share.
Why does volume solids change the gallons so much? Only the solids stay on the part; the solvent leaves. A 60% solids enamel delivers 0.6 gallons of film per liquid gallon, so the requirement rises by two-thirds.
Is this the right page for powder coating? No. Powder build runs on pounds and specific gravity, not liquid gallons. The powder coverage page on this hub is the powder twin of this calculation.

Last reviewed 2026-10-01.