How much does one gallon of paint cover?

A practical planning average is about 350 square feet per gallon per coat.

Should I include the ceiling?

Include it when repainting the whole room or changing ceiling color; otherwise walls alone are enough.

This calculator uses about 20 square feet per door and 15 square feet per window.

Inputs

Change any field and the results update instantly. Use supplier specs when you have them.

Room lengthftRoom widthftWall heightftCoatsDoorsWindowsCoveragesq ft/galTexture waste%Trim lengthftTrim widthinInclude ceiling

Tips & notes

Assumptions that most often change the final quantity in the field—so you order with clearer eyes.

Use two coats for major color changes or fresh drywall.

Textured walls and deep colors need more paint than smooth, primed walls.

Subtracting openings helps, but buy a little extra for touch-ups.

Use separate products for walls, trim, and ceilings when finish sheen matters.

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