Paint Coverage Per Gallon Guide
Paint coverage is one of the main inputs in a gallon estimate. Use the coverage printed on your product whenever it is available.
Start with the paint calculator
Enter your room dimensions, number of coats, and product coverage in the ATHENA Paint Calculator. The calculator uses the coverage value you provide to convert paintable area into gallons.
How paint coverage affects the estimate
The basic relationship is:
Paint needed = paintable area × coats ÷ coverage per gallon
A lower coverage rate means more gallons are needed for the same paintable area. A higher coverage rate means fewer gallons, assuming the other inputs stay the same.
What coverage should I enter?
Use the manufacturer's stated coverage from the exact paint product you plan to use. ATHENA starts with 350 square feet per gallon as a default planning value and allows you to change it.
Example: 700 square feet with two coats
For 700 square feet of paintable area and two coats, a product rated at 350 square feet per gallon gives 700 × 2 ÷ 350 = 4 gallons before the calculator's 10% planning allowance.
If the same area uses a product rated at 400 square feet per gallon, the coverage-based result is 3.5 gallons before the planning allowance. The product's actual label coverage should take priority over a general default.
Why actual coverage can differ
Surface texture, porosity, color changes, application method, and the product itself can affect actual paint usage. Rough or absorbent surfaces may use more material than a smooth, previously coated surface.
Coverage, coats, and paintable area
Coverage is only one part of the estimate. Make sure the area represents the surfaces you actually plan to paint, then include the correct number of coats. Doors, windows, and ceilings can change the paintable area and should be handled consistently with your project plan.
Ready to calculate?
Use the Free Paint Calculator, read Paint Coverage Calculator Guide, or see How Much Paint Do I Need?.
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