Deck Paint Calculator
Deck paint, solid stain and resurfacer coatings are film-forming, so they go on in two coats and the coverage depends heavily on the product: a thick resurfacer covers about a quarter of what porch paint does. This adds the railing and stair surfaces to your deck area, applies the right coverage and coat count for the product, and gives the gallons, primer and cost to buy.
Coverage by product
| Product | Coverage per coat | Coats | Gallons for 300 sq ft |
|---|---|---|---|
| Porch & floor paint | ~300 sq ft/gal | 2 | 2 |
| Solid-colour deck stain | ~250 sq ft/gal | 2 | 3 (2.4) |
| Resurfacer / restore coating | ~150 sq ft/gal | 2 | 4 |
| Exterior primer | ~300 sq ft/gal | 1 | 1 |
These are typical figures from manufacturer labels on smooth, sound wood. Weathered or rough-sawn boards soak up more — allow up to a quarter extra on an old deck.
Worked example
A 200 sq ft deck with 40 ft of railing and four steps: the railing adds 40 × 2 = 80 sq ft (both faces, rails and balusters) and the steps add 4 × 4.6 ≈ 18 sq ft, so the surface is about 298 sq ft. Two coats of porch paint at 300 sq ft per gallon is 298 × 2 ÷ 300 = 1.99, so 2 gallons. The same deck in resurfacer is 298 × 2 ÷ 150 = 3.98, 4 gallons.
Paint, solid stain or resurfacer?
- Porch & floor paint gives the most colour choice and covers the most area per gallon, but a painted floor shows wear in traffic lanes.
- Solid stain is thinner and more breathable than paint, so it is less likely to peel on a deck floor.
- Resurfacer is a thick coating that fills cracks and splinters on tired but solid boards. It needs a lot of product and fails fast over rot.
If you want the grain to show, you want a penetrating stain instead — the deck stain calculator handles one-coat and Ready Seal products. Hiring the job out? The deck refinishing cost calculator prices the prep and labour, and our best deck paint guide compares the products.
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Frequently asked questions
- How much paint do I need for my deck?
- Divide the surface by the coverage and multiply by two coats. Porch and floor paint covers about 300 sq ft per gallon per coat, so a 200 sq ft deck with 40 ft of railing and four steps is about 298 sq ft of surface and just under 2 gallons for two coats. Buy 2 plus one for touch-ups.
- How much does a gallon of deck resurfacer cover?
- Much less than paint: thick resurfacer or restore coatings are rated at roughly 75 sq ft per gallon for the two coats they need, about a quarter of what porch paint covers. That is why a resurfaced 200 sq ft deck with railings takes about 4 gallons where paint would take 2. They fill cracks and splinters, but they peel if the boards underneath are rotten.
- Should I paint or stain my deck?
- Stain penetrates the wood and wears away gradually, so it is easy to recoat. Paint and solid stain form a film that hides worn or mismatched boards and lasts longer on vertical surfaces, but it peels when water gets under it and has to be scraped before recoating. Paint suits railings and older decks; penetrating stain suits floors on newer ones.
- Do I need to prime a deck before painting?
- Prime bare wood, new pressure-treated lumber once it is dry, and any patched or stripped areas. A deck that was painted before and is still sound only needs cleaning and a light scuff. One coat of exterior primer at about 300 sq ft per gallon is enough; the calculator adds it when you choose to prime.
- How many coats of deck paint do I need?
- Two. Deck paint, solid-colour stain and resurfacers are all film-forming finishes, and their durability comes from film thickness, which one coat does not give. Let the first coat dry for the time on the can, usually 4 to 24 hours, and apply the second before the recoat window closes.
