BUILDREFS Free Tools

Paint Coverage Calculator

Estimate paint gallons, primer, roller covers, and brushes for interior or exterior projects. Doors and windows automatically deducted.

Surface Type

Coverage rate: 400 SF per gallon

Number of Coats

Include Ceiling

Include Primer

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Doors

Deducted at 21 SF each

Windows

Deducted at 15 SF each

Coverage Rates

Surface	SF / Gal
Smooth Wall	400
Textured Wall	300
Ceiling	350
Exterior Siding	300
Masonry/Block	150
Raw Wood	200

How Many Coats?

1 coat: Touch-up or same color repaint.
2 coats: Standard new paint job over primer.
3 coats: Dark to light color change, or raw drywall.

Field Tips

• Always prime new drywall — paint soaks in unevenly without it.
• Buy 10% extra — dye lots vary, hard to match later.
• Use a ⅜" nap roller for smooth walls, ¾" for textured.
• Cut in edges with a brush before rolling large areas.
• Allow 2–4 hours between coats (check label).

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