Paint Sheen Coverage Calculator
See how paint sheen changes real coverage — flat stretches further, gloss covers less — and get the gallons and cost for your wall.
How it works
Gallons = area × coats ÷ coverage-per-gallon · Cans = round up · Cost = cans × price
A gallon of paint does not cover a fixed number of square feet — the higher the sheen, the thinner and more uniformly it must be spread to look right, so glossier finishes stretch a little less far than flat paint. Manufacturers quote roughly 400 sq ft/gal for flat down to about 340 for high gloss. Because you can only buy whole cans, the practical answer is always rounded up.
Worked example
A 300 sq ft wall in two coats of satin covers 600 sq ft of surface. At satin’s ~360 sq ft/gal that is 600 ÷ 360 = 1.67 gal, so you buy 2 gallons; at $45 each that is $90.
Frequently asked questions
Why does sheen change how far paint goes?
Glossier paints show every ridge and thin spot, so they are applied in a more even, slightly thinner film and are less forgiving over porous or patchy surfaces. Flat paint hides imperfections and can be laid on a touch heavier, which is why it is quoted at a higher square-footage per gallon.
Does the first coat use more paint?
Often yes — a bare, porous or previously unpainted wall soaks up the first coat, so real-world first-coat coverage can be 10–20% lower than the label figure. The second coat usually meets or beats the quoted rate.
Should I round up per color or overall?
Round up separately for each color and each sheen, since you cannot blend leftover gloss into a flat can. Keeping a little extra of each is also useful for touch-ups later.
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This calculator is for educational purposes. Double-check important results before acting on them.