How Much Paint for a 15×20 Room?

Answer
2.9 gal walls, 2 coats

A 15 × 20 ft room with 8 ft ceilings has 509 sq ft of wall after subtracting one door and two windows. Two coats at 350 sq ft per gallon take 2.9 gallons; add 1.7 gallons to paint the ceiling.

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Most interior paints: 350–400 sq ft/gal.
Paint needed
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How we calculated this

    For estimating and educational purposes only. Results are approximate and are not a substitute for a licensed professional, the manufacturer's instructions or your local code. Disclaimer

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    Paint by ceiling height (walls, 2 coats)

    Ceiling heightWall areaPaint
    8 ft509 sq ft2.91 gal
    9 ft579 sq ft3.31 gal
    10 ft649 sq ft3.71 gal

    Door counted as 21 sq ft and each window as 15 sq ft. Buy whole gallons; three quarts cost about the same as a gallon.

    Frequently asked questions

    How many gallons of paint for a 15x20 room?

    About 3 gallons for two coats on 8 ft walls, and 2 more for the ceiling.

    Do I need primer?

    Use primer on new drywall, patches, stains or when changing from a dark to a light color.

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