Solve backwards
How big a deck will my stain cover?
- 2 galThe example worked below
- Deck Stain CalculatorEvery figure is its own
You have
How much deck stain?
That is 2 gal(7.6 L). Worked by the Deck Stain Calculator at the settings below.
The settings it uses
- Number of Coats
- 1
What it will do
400 sq ft of deck
37.2 m²
One deck. Enough for a deck about 20 × 20 ft.
Or several. About 1 deck of the size the Deck Stain Calculator opens on: a deck about 14.8 × 14.8 ft.
Check it forwards
- Deck Area
- 400 sq ft
- It asks for
- 2 gal
- You have
- 2 gal
The Deck Stain Calculator asks for 2 gal at that size, and 3 gal one step larger.
If you had more, or less
Around your amount
Each worked by the Deck Stain Calculator at the same settings.
Half
1 gal
200 sq ft
a deck about 14.1 × 14.1 ft
Yours
2 gal
400 sq ft
a deck about 20 × 20 ft
Half as much again
3 gal
600 sq ft
a deck about 24.5 × 24.5 ft
Double
4 gal
800 sq ft
a deck about 28.3 × 28.3 ft
Common amounts
What each amount of deck stain covers
The sizes it is usually sold in, each worked by the Deck Stain Calculator at the settings above.
| You have | It covers | As one deck | Average decks |
|---|---|---|---|
| 1 gal(3.8 L) | 200 sq ft(18.6 m²) | a deck about 14.1 × 14.1 ft | under 1 |
| 2 gal(7.6 L) | 400 sq ft(37.2 m²) | a deck about 20 × 20 ft | 1 |
| 3 gal(11.4 L) | 600 sq ft(55.7 m²) | a deck about 24.5 × 24.5 ft | 1 |
| 5 gal(18.9 L) | 1,000 sq ft(92.9 m²) | a deck about 32 × 32 ft | 2 |
The timber sets the rate, not the label
The calculator holds 200 square feet per US gallon per coat, about 19 m² per 3.8 litres, the bottom of the 200 to 300 range its source quotes. New, dense or previously coated boards take less than that, and weathered, rough-sawn decking drinks more — the same stain can halve its coverage on a board that has been down two summers.
Deck area is not stained area
Balusters, rails, posts, fascia, stair stringers and the edges of every board are surface no floor-area figure contains, and on a deck with a substantial balustrade the rail work can come close to the deck itself. The deck here is the flat walking surface, so keep stain back for the rest.
Whole gallons, and one coat to start
The calculator rounds up to whole US gallons, so the deck here is the largest one whose rounded requirement fits what you have. It opens at one coat, standard for maintenance; new or bare wood often wants two, and a second coat on sealed boards goes much further than the first, so two coats is rarely twice one.
How the answer is worked
Nothing here is a second formula. The Deck Stain Calculator runs forwards — a size in, a quantity out — and this page grows its own starting deck in proportion until the quantity it asks for is what you have. Where it rounds up to whole containers, the answer is the largest size before the next one would be needed.
Where the calculator adds an allowance for cuts or breakage when you order, the same allowance comes off here, because it is the same calculator: a stack you already own finishes less than its face value. Where it adds none, neither does this page — the settings beside the answer say which.
Deck Stain Calculator
runs it forwardsEstimate how many gallons or litres of deck stain or sealer you need to cover your deck.
Work out what to buy insteadSolve backwards
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Solve backwards
Start from what is already in the yard
Paint, sheets, rolls, bags and pieces, each read the other way by the calculator that orders it.
The calculator's own figures
Nothing is estimated twice: the page runs the same calculator you would order with.
The largest size that fits
Where a calculator rounds up to whole containers, the answer stops before the next one.
Both unit systems
Gallons and litres, square feet and square metres, side by side.
Frequently asked questions
- How much deck does 2 gal of deck stain cover?
- At the Deck Stain Calculator's own settings, 400 sq ft (37.2 m²) — a deck about 20 × 20 ft. That is about 1 deck of the size the calculator opens on: a deck about 14.8 × 14.8 ft. Every figure follows the settings, which you can change in the calculator.
- How much deck does 10 L of deck stain cover?
- At the Deck Stain Calculator's own settings, 37.2 m² (400 sq ft) — a deck about 6.1 × 6.1 m. That is about 1 deck of the size the calculator opens on: a deck about 4.5 × 4.5 m. Every figure follows the settings, which you can change in the calculator.
- How many square feet does a gallon of deck stain cover?
- About 200 to 300 square feet per US gallon per coat, roughly 19 to 28 m² per 3.8 litres, depending on how porous the wood is and how opaque the stain. The calculator uses 200 so that a thirsty deck is not left short; a smooth, previously sealed deck will go further.
- How many coats of stain does a deck need?
- One is standard for routine restaining. New or bare wood often wants two, and some solid-colour stains need two for full opacity. The second coat goes much further than the first because the boards are already partly sealed — check your product's own recommendation.
- Why did my deck stain run out before the deck was finished?
- Usually because the rails, balusters, posts, stair stringers and board edges were never in the area — they are all stainable surface that a length-times-width measurement leaves out. Weathered boards that drink the first coat, and stain left in the pad and dripped through the gaps, account for the rest.