Paint Calculator

Subtract openings from wall area and divide by coverage. The default is 350 square feet per gallon.

Smart Tips

• Measure each wall as length times height, in feet.

• Subtract doors and windows as one opening total.

• Two coats double the gallons.

• 350 square feet per gallon is the starting coverage. Change it.

• If openings are larger than the walls, the page stops instead of showing negative gallons.

The Formula

gallons = (wall area − openings) × coats ÷ coverage

wallSum of length × height for every wall row.

openingsSquare feet you subtract once.

coatsHow many times that area is painted.

350Default square feet per gallon. The field is editable.

A 20 by 8 wall is 160 square feet. Minus 20 square feet of openings, times 2 coats, divided by 350, is 0.8 gallons.

Key Insights

Net area

Openings come off before the coats are applied.

Editable coverage

350 is a planning default, not the only paint on the shelf.

Several walls

Add a row per wall. The rows are summed.

Zero height

A wall with no height adds no area and no gallons.

Frequently Asked Questions

Use Add wall. Each row is length times height in feet. The rows are added, then the opening total is subtracted once.

The square feet of doors and windows you will not paint. A 20 by 8 wall minus 20 square feet of openings leaves 140 square feet.

That is the low end of the 350 to 400 square feet per gallon range Sherwin-Williams prints for a typical gallon. Your can may differ. Change the field and the gallons follow it.

Gallons = paintable square feet × coats ÷ coverage. Two coats of the 140 square foot example at 350 square feet per gallon is 0.8 gallons.

The page reports that the openings exceed the wall area and does not divide a negative area.

Gallons equal paintable square feet times coats, divided by coverage. Paintable area is wall length times height, minus the openings you enter. The default coverage is 350 square feet per gallon, the low end of the 350 to 400 square feet per gallon range Sherwin-Williams prints for a typical gallon. www.sherwin-williams.com/en-us/color/color-tools/paint-calculator

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Gallons

Enter wall size and openings

Gross sq ft

Paintable sq ft

Coverage

Note:Gallons use the coverage in the form. It starts at 350 square feet per gallon, the low end of the 350–400 range Sherwin-Williams prints for a typical gallon. Edit it to match the can.