Easy Paint Calc

How much paint for a 12×12 deck?

Short answer

A 12 × 12 ft deck floor (144 square feet) needs about 1.44 gallons of deck paint or solid-color stain for two coats at 200 square feet per gallon. Buy 1 gallon + 2 quarts.

How to work it out

  1. Floor: 12 ft × 12 ft = 144 sq ft
  2. 144 sq ft × 2 coats ÷ 200 sq ft/gal = 1.44 gal → 1 gallon + 2 quarts

A 12 × 12 ft platform deck is 144 sq ft of boards. With deck paint or a solid stain at the low end of the 200–400 sq ft per gallon range, two coats come to just under a gallon and a half. A railing around three sides nearly doubles that.

Adjust for your project

ft
ft
ft
Optional. Balusters 1½ in square, 3½ in apart, with two rails, painted all round
Solid stain and deck paint: two coats. Semi-transparent: one or two, per the label
More options: Rail H · Steps · Stair W …
in
Tread and riser of each step
ft
sq ft/gal
Leave blank to use the planning figure for the product above
%
Optional. Data-sheet coverage leaves out spray loss; add 10–25% if you spray
Buy (gallons and quarts)1 gallon + 2 quarts
Deck paint or stain needed
1.44 gal (5.45 L)
Cans of the size you chose
2 cans · 1-gallon
Surface to coat (one coat)
144 sq ft
Paint per coat
0.72 gal
Coverage used
200 sq ft/gal
  • Using a planning coverage for this product. Weathered, rough and soft woods soak up more; your can’s figure is better.
  • Board edges and gaps take a little extra; the deck floor is counted as flat.
  • Deck paints and solid stains form a film that can peel on horizontal boards. Clean and dry the wood thoroughly and follow the label’s recoat window.
  • Old house? If it was built before 1978, read lead paint safety before you sand or scrape: EPA advises assuming old paint contains lead until it is tested.

For this job · affiliate link
Deck stain pad and poleA pad on a pole lays 1 gallon + 2 quarts down across the boards evenly and works it into the gaps, standing up.
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Deck coating by product (same deck and coats)

Deck coating by product (same deck and coats)
ProductDeck paint or stain neededBuy (gallons and quarts)
solid stain or deck paint1.44 gal1 gallon + 2 quarts
semi-transparent stain1.15 gal1 gallon + 1 quart
stain on weathered wood1.92 gal2 gallons

What to know about coating a 12×12 deck

  • Floor only: 1.44 gallons. 144 × 2 ÷ 200. A gallon and two quarts, or two gallons if the boards are old and thirsty.
  • With a railing on three sides (36 ft): balusters and rails add about 190 sq ft, so two coats come to about 3.3 gallons. Railings are slow, brush-heavy work; many people stain them before the floor.
  • Semi-transparent stain: one coat on newer wood is about 0.58 gallons; on weathered boards, about a gallon.
  • Steps. Four 4 ft steps add about 25 sq ft; set them under More options.

Paint and solid stain on a horizontal deck are a commitment: the film wears in traffic paths and has to be recoated, and peeling paint has to be scraped before the next coat. Semi-transparent stains wear away rather than peel. Whichever you choose, coat a test board first so you can see the color on your wood.

Smaller and bigger versions: how much paint for a 10x10 deck and how much paint for a 12x16 deck. A pail of exterior paint’s coverage is on how much does a 5 gallon bucket of paint cover.

Different size? Use the full Deck Paint & Stain Calculator.

What you’ll need

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Frequently asked questions

How much paint for a 12x12 deck with railings?

With 36 ft of railing, about 3.34 gallons for two coats: 3 gallons + 2 quarts.

How much semi-transparent stain for a 12x12 deck?

About 0.58 gallons for one coat on newer wood: 1 gallon.

Other common sizes

Sources