Coverage Rate
general
How much area one unit of a material covers — square feet per gallon of paint, per bag of mulch, or per ton of gravel at a given depth.
Coverage rates are always stated at a specific thickness or depth, and that qualifier is what makes them useful or misleading. A ton of gravel covers 125 square feet at 2 inches and 63 at 4 — the same material, half the area, because depth doubled. Paint coverage is quoted for a smooth, previously painted surface; bare drywall, fresh stucco, and rough-sawn wood can halve it. Manufacturer figures are laboratory conditions with an experienced applicator, so treat them as a ceiling rather than a working average.
Formula
Units needed = area ÷ coverage rate × coats
Example
A 356 ft² wall at 350 ft²/gal in two coats: 356 × 2 ÷ 350 = 2.03 gallons.
Common mistake
Applying a coverage rate without checking the depth or surface it assumes. Most disputes about "not enough material" trace back to a rate quoted at a different thickness than the one being installed.
Use the Paint Calculator
Calculate gallons of paint and primer for any project. Defaults to 350 ft²/gallon coverage and 2 coats — adjust for textured surfaces.
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