Deck Stain Calculator
How much stain a deck or fence takes, counting the floor, both faces of the railing and the stairs, from the coverage on the can and the number of coats.
Result
Enter coverage per coat on the label to see the result.
https://calcgallery.com/decking-fencing/deck-stain-calculator/
Results are estimates for planning only. Actual needs vary with site conditions, products and workmanship. Always confirm quantities with your supplier and follow local building codes and manufacturer instructions. Read the full disclaimer
How to use the Deck Stain Calculator
- Choose deck or fence. For a deck, enter the floor's length and width, the length and height of any railing, and the steps.
- Enter the number of coats and the coverage per coat printed on the can, in square feet per gallon or square metres per litre.
- Enter the container size to see how many to buy.
The areas
deck floor = length × widthrailing = 2 × railing length × railing heightstairs = steps × stair width × (tread depth + riser height)fence = length × height × sidesstain = total area × coats ÷ coverage per coatcontainers = stain ÷ container size, rounded upEvery surface is flattened to its area before the coverage is applied, so the only product figure in the calculation is the coverage from the can.
Why the result can differ from the can
Penetrating stains soak into dry, weathered or rough-sawn wood and cover less area than a label figure measured on smooth boards; solid stains behave more like paint. A test board of your own deck, stained and measured, is the most reliable coverage figure there is.
With your numbers
- Area = deck floor + 2 × railing length × height + steps × width × (tread + riser)
- Stain = area × coats ÷ coverage per coat
Quick reference
Containers round up; porous wood can take more than the label says.
| Job | Stain needed |
|---|---|
| 16 × 12 ft deck, 1 coat at 250 ft²/gal | 0.77 gal |
| 16 × 12 ft deck with railing, 2 coats at 200 ft²/gal | 4.32 gal |
| 16 × 12 ft deck, railing and 4 steps, 2 coats at 200 ft²/gal | 4.56 gal |
| 20 × 14 ft deck, 2 coats at 150 ft²/gal | 3.73 gal |
| 100 ft fence, 6 ft, both sides, 1 coat at 250 ft²/gal | 4.8 gal |
| 100 ft fence, 6 ft, one side, 1 coat at 250 ft²/gal | 2.4 gal |
| 5 × 4 m deck with railing, 2 coats at 8 m²/L | 10.4 L |
Common questions about the Deck Stain Calculator
- How many cans of deck stain do I need?
- Five 1-gallon cans for a 16 by 12 foot deck with 40 feet of 3-foot railing and four 4-foot-wide steps with 11 inch treads and 7 inch risers, given two coats at 200 square feet per gallon. The area is 192 + 240 + 24 = 456 square feet, so two coats take 912 ÷ 200 = 4.56 gallons, rounded up to 5 cans.
- How much stain do I need for a 16 by 12 foot deck?
- The floor is 192 square feet. At a coverage of 250 square feet per gallon, one coat takes about 0.77 gallon; a second coat doubles it. Railings and stairs add a lot: 40 feet of 3-foot railing is another 240 square feet once both faces are counted, more than the floor itself.
- Why does the page count both sides of the railing?
- Because you stain both. The page treats the railing as a solid panel on each face. Balusters with gaps between them have less face area than that, but their edges add some back, and a solid panel is a sensible upper figure for buying.
- What coverage should I use?
- The figure on your can, which varies by product and by the wood. Many labels give a range; new, smooth wood takes the high end and weathered or rough wood the low end. The second coat usually goes further than the first, so using the first-coat figure for both errs on the generous side. The worked example uses 200 square feet per gallon (8 m² per litre), while the calculator leaves the field blank so you enter the figure from your can.
- Does it include the stair stringers and fascia?
- No. It counts each step’s tread and riser across the stair width. Stringer sides, fascia boards and posts are extra; add their area to the deck by increasing the length or width slightly, or buy one more container.