Deck stain calculator
How much stain a deck needs: the surface area of the boards, the railing and the stairs, divided by the coverage of your stain — which drops for solid stains and for rough or weathered wood — times the number of coats. Enter dimensions and it returns the gallons and, optionally, the cost.
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All Building & renovation tools →Enter Deck length (ft), Deck width (ft), Railing length (ft), Number of stairs, Stain type, Wood surface, Number of coats, Price per gallon and the Deck stain calculator works out Total surface area (ft²), Gallons needed, Litres needed, Estimated cost straight away. For instance, with Deck length (ft) = 20, Deck width (ft) = 16, Railing length (ft) = 40, Number of stairs = 4, Stain type = Transparent / sealer, Wood surface = Smooth / new, Number of coats = 2 and Price per gallon = $35.00 it returns Total surface area (ft²) = 544, Gallons needed = 3.627 and Litres needed = 13.728.
How to use it
- Enter your values: Deck length (ft), Deck width (ft), Railing length (ft), Number of stairs, Stain type, Wood surface, Number of coats, Price per gallon.
- Read the result instantly: Total surface area (ft²), Gallons needed, Litres needed, Estimated cost.
Frequently asked questions
How does the Deck stain calculator work?
It takes Deck length (ft), Deck width (ft), Railing length (ft), Number of stairs, Stain type, Wood surface, Number of coats and Price per gallon and derives Total surface area (ft²), Gallons needed, Litres needed and Estimated cost from them. The calculation is live as you type, so the result updates on every change.
Which values does the calculator ask for?
8 values: Deck length (ft), Deck width (ft), Railing length (ft), Number of stairs, Stain type, Wood surface, Number of coats and Price per gallon ($). Nothing else is required — no account, no file upload.
What does a typical calculation look like?
With Deck length (ft) = 20, Deck width (ft) = 16, Railing length (ft) = 40, Number of stairs = 4, Stain type = Transparent / sealer, Wood surface = Smooth / new, Number of coats = 2 and Price per gallon = $35.00, the calculator returns Total surface area (ft²) = 544, Gallons needed = 3.627 and Litres needed = 13.728. Those figures come from running this exact tool, so you can reproduce them by entering the same values.
How much does the result change with different inputs?
It moves a lot. Using Deck length (ft) = 40, Deck width (ft) = 32, Railing length (ft) = 80, Number of stairs = 8, Stain type = Semi-transparent, Wood surface = Weathered / grey, Number of coats = 4 and Price per gallon = $70.00 instead, Total surface area (ft²) goes from 544 to 1,856 — which is why it is worth testing a few scenarios rather than trusting a single figure.
Which “Stain type” option should I choose?
You can pick between « Transparent / sealer », « Semi-transparent », « Semi-solid » and « Solid / opaque ». Each one changes what the calculator works out, so switch and compare — the default is « Transparent / sealer ».
What does it give for smaller values?
Scaled down to Deck length (ft) = 10, Deck width (ft) = 8, Railing length (ft) = 20, Number of stairs = 2, Stain type = Transparent / sealer, Wood surface = Smooth / new, Number of coats = 1 and Price per gallon = $18.00, Total surface area (ft²) comes out at 176. The relationship is worth checking at both ends before you rely on a single result.
When would I actually use this?
Buying the right amount at the merchant: how many tiles, how much paint, how many bags of concrete, and what it all comes to.
What is the most common mistake?
Ordering the exact calculated quantity. Cuts, breakage and pattern matching mean tiles need 10% spare and more on a diagonal layout — and a second batch rarely matches the first for colour.
How accurate is it, and what are the limits?
Estimate only — coverage varies by product and application.
What is the difference between the Deck stain calculator and the Brick calculator?
This one returns Total surface area (ft²) and Gallons needed; the Brick calculator returns Bricks needed and Bricks per m². That is the whole difference — open the one whose figure you need.