How much fence stain you need
A fence is not a flat wall: pickets have edges, rails and posts stick out on one side, and board on board fences hide strips where the boards overlap. So the calculator first works out the surface a brush or sprayer actually reaches, then divides by the coverage on the data sheet for your product, once per coat.
gallons = fence length × surface per foot for your style and sides × coats ÷ coverage per gallon
We give a range because every manufacturer does: the smaller number uses the high end of the coverage, the larger number the low end. Buy for the larger number, so a thirsty fence doesn't leave you short halfway down the line.
Worked example
A 150 ft privacy fence, 6 ft high, 1x6 boards butted tight, stained on both sides with Cabot Semi-Transparent Stain + Sealer on smooth boards:
- Board side: 6.00 sq ft per foot of fence, exactly the flat face.
- Rail side: 7.19 sq ft per foot. The three 2x4 rails and the 4x4 posts add their exposed faces and edges, less the strip of board they cover.
- Surface: (6.00 + 7.19) × 150 = 1,978 sq ft for one coat.
- Cabot lists 450 to 650 sq ft per gallon on smooth wood and one coat, so 1,978 ÷ 650 to 1,978 ÷ 450 = 3 to 4.4 gallons. One 5 gallon pail covers it.
If the boards are rough sawn, Cabot's coverage drops to 200 to 300 sq ft per gallon and the same fence takes 6.6 to 9.9 gallons, two pails. Texture changes the answer more than anything else you enter.
Surface per foot by fence style
These are the numbers behind the style picker, from the same board sizes the fence calculator uses. The surface factor is the stained area divided by length × height for each side you stain.
| Style (default boards) | Board side | Rail side | Both sides |
|---|---|---|---|
| Solid privacy, 6 ft, 1x6 butted | 6.00 sq ft (1.00×) | 7.19 sq ft (1.20×) | 13.19 sq ft |
| Board on board, 6 ft, 1x6 with 1 in overlap | 7.29 sq ft (1.22×) | same | 14.58 sq ft |
| Shadow box, 6 ft, 1x6 with 3.5 in gaps | 7.29 sq ft (1.22×) | same | 14.58 sq ft |
| Picket, 4 ft, 1x4 with 2.5 in gaps | 3.14 sq ft (0.78×) | 3.93 sq ft (0.98×) | 7.07 sq ft |
| Split rail, 3 rails | 2.30 sq ft | same | 4.60 sq ft |
Why they differ:
- Gaps remove face area but add edges. A 4 ft picket fence has only 58% of its face in wood, but every 3/4 in picket edge is stained too, and through the gaps you reach the rails behind.
- Board on board and shadow box are two layers. From either side you stain the near boards, their edges, and the far boards where they show through the gaps, which adds up to more than a flat face. The strips where the layers overlap, 1.33 sq ft per foot per side on a 6 ft fence, are not counted: a brush can't get between them, and a sprayer only reaches part of the way.
- The rail side is always bigger. Rails and posts add about 20% on a solid fence.
- Split rail has no boards. We take each rail as roughly 3 by 5 in (16 in around), with 6 in round posts every 10.5 ft, and count half of every surface for each side.
Chain link is left out: it is not stained. The privacy fence calculator and the board on board fence calculator count the lumber for these styles.
Coverage by brand
| Product | Smooth | Rough | Coats |
|---|---|---|---|
| Cabot Semi-Transparent Stain + Sealer | 450 to 650 | 200 to 300 | 1 |
| Behr Premium Semi-Transparent Stain & Sealer | 250 to 300 first coat, 500 to 600 second | not split | 2 required |
| Sherwin-Williams WoodScapes Rain Refresh | 300 to 400 | 200 to 300 | 2 recommended |
| Thompson's WaterSeal Transparent Wood Sealer | 150 to 400, by porosity | not split | 1 |
All figures are square feet per gallon per coat, from each manufacturer's data sheet. Behr lists about twice the coverage for the second coat, so the calculator uses the higher number from the second coat on. On the example fence, Behr's two coats come to 9.9 to 11.9 gallons, and two coats of WoodScapes to 9.9 to 13.2. If your stain isn't listed, pick "Other stain" and type the coverage from the can.
What staining a fence costs
HomeAdvisor prices stain at $20 to $50 a gallon for doing it yourself, so the Cabot example costs $80 to $250 in stain. Hired, HomeAdvisor gives $3 to $14 per linear foot, which is $450 to $2,100 for 150 ft. Homewyse prices one coat of semi-transparent oil stain at $1.38 to $2.76 per square foot of surface, $2,730 to $5,460 for the same 1,978 sq ft. The two sources measure differently, so compare quotes on the same basis. The fence painting cost calculator sets the hired price against doing it yourself for paint as well as stain.
Do you need to stain both sides?
Only if you want both protected; the calculator lets you pick the board side, the rail side or both. Fixr notes that per foot prices roughly double when both sides are finished, and HomeAdvisor's per foot rate does not say which sides it covers, so ask whether a quote includes one side or both.