Deck Paint Calculator
Deck paint covers less per gallon than stain because it sits on the surface instead of soaking in. Enter your deck dimensions and coats to get an accurate gallon count.
Result
- Deck area192sq ft
- Total coated area192sq ft
- Paint needed4gallons
- Exact before rounding3.84gallons
- Metric14.5litres
How it works
paint = (area ÷ coverage per gallon) × coats, rounded up to the nearest half gallon
- Deck area = 16 × 12 = 192 sq ft
- Top face only = 192 sq ft
- 2 coats at 100 sq ft/gal = 3.84 gallons
- Round up to nearest half gallon = 4 gal
How the deck paint calculator works
Paint coverage is always quoted per coat. Rough wood takes more because the surface area and absorption are both higher — about 100 sq ft per gallon versus 150 for smooth.
Two coats are standard for a durable deck finish: the first primes and binds, the second evens the film. Double your area before dividing by coverage.
Round up to the nearest half gallon. Paint from one batch covers uniformly; two cans from different lots can show a seam.
Formula
gallons = (area ÷ coverage per gallon) × coats, rounded up to ½ gal
Worked example: 192 sq ft deck, one coat
- Deck area = 12 × 16 = 192 sq ft
- Smooth surface: 150 sq ft per gallon
- One coat = 192 ÷ 150 = 1.28 gallons
- Round up to nearest half gallon = 1.5 gallons
- Two coats = 192 ÷ 150 × 2 = 2.56 → 3 gallons
Paint coverage by surface
| Surface | Coverage per gallon | 100 sq ft, 1 coat | 200 sq ft, 1 coat |
|---|---|---|---|
| Rough / pressure-treated | 100 sq ft | 1 gallon | 2 gallons |
| Smooth / sanded | 150 sq ft | 0.67 → 1 gallon | 1.33 → 1.5 gallons |
Coverage per coat. Exterior deck paints typically need two coats for even color.
Frequently asked questions
How much paint do I need for a 12×16 deck?
192 sq ft. Smooth surface at 150 sq ft/gal: one coat needs 1.28 gallons → buy 1.5; two coats need 2.56 → buy 3 gallons. Rough pressure-treated wood at 100 sq ft/gal needs 2 gallons per coat.
Should I paint or stain my deck?
Stain penetrates and wears gradually, making touch-ups invisible. Paint forms a film that can peel on horizontal surfaces but hides weathering and old wood. Most builders recommend stain for deck floors and paint only for railings and vertical trim.
How many coats of deck paint are needed?
Two coats for a new or fully stripped deck: one to prime the surface, one to build the film. A repaint over sound existing paint may need just one coat.
Do I need primer before painting a deck?
On bare wood, yes — or use a paint-and-primer-in-one rated for decks. On previously painted surfaces in good condition, a light sand and clean is usually enough before the topcoat.