How Much Paint for a 12×16 Room?

Quick Answer

A 12×16 room with 8-foot ceilings has about 412 square feet of paintable wall after subtracting a door and window. Two coats need about 3 gallons of paint. Add about 1 gallon if you are also painting the 192 square foot ceiling.

  • Wall area: ~412 sq ft (after door and window)
  • Two coats of walls: ~3 gallons
  • Ceiling (192 sq ft): about 1 gallon
  • 1 gallon covers about 350 sq ft per coat

Formula

Gallons = (Wall Area × Coats) ÷ 350

Find wall area by multiplying room perimeter by ceiling height, then subtract openings. Multiply by the number of coats and divide by 350 square feet of coverage per gallon.

Step-by-Step Calculation

  1. 1

    Wall area (gross)

    (12+16+12+16) × 8 = 448 sq ft

  2. 2

    Subtract openings

    448 − 21 (door) − 15 (window) = 412 sq ft

  3. 3

    Two coats

    412 × 2 = 824 sq ft to cover

  4. 4

    Gallons needed

    824 ÷ 350 = 2.35 → 3 gallons

Paint by Room Size (8-ft ceilings, 2 coats)

Room SizeWall AreaCoverage NeededGallons
12×12348 sq ft696 sq ft2 gallons
12×16412 sq ft824 sq ft3 gallons
14×16444 sq ft888 sq ft3 gallons
16×20540 sq ft1,080 sq ft4 gallons

Assumes one door and one window per room. Deep or bold colors over a light wall may need a primer coat plus two finish coats.

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Frequently Asked Questions

How many gallons of paint for a 12×16 room?

About 3 gallons for two coats on the walls, plus roughly 1 gallon for the ceiling. Buying the third gallon avoids running short mid-wall, and leftover paint is handy for touch-ups.

Do I need primer for a 12×16 room?

Prime new drywall, patched areas, or when making a big color change. A separate primer coat adds about 1 to 1.5 gallons; paint-and-primer products can reduce that on already painted walls in good condition.

How much does it cost to paint a 12×16 room?

Paint runs about $90–$180 for 3 to 4 gallons of quality product. A professional interior paint job for a room this size typically costs $400–$800 including labor, prep, and materials.