Fence Stain Calculator
Calculate how much fence stain or paint you need based on fence size, style, and number of coats.
Did this tool work for you?
How to use this calculator
Adjust gross area by fence style (solid=100%, picket=50%, split-rail=30%), then divide by coverage per litre and multiply by coats.
- 1
Measure your fence length and height in metres.
- 2
Select whether you are painting one or both sides.
- 3
Choose your fence style to account for open areas.
- 4
Enter the stain or paint coverage per litre from the product label.
- 5
Select the number of coats you plan to apply.
Frequently asked questions
What formula does the fence stain calculator use?
Paintable area = length × height × sides × style factor. Litres = paintable area × coats ÷ coverage per litre. The tool then adds 10% to the litres and rounds up to whole 4 litre cans.
What are the style factors?
Solid board counts as 100% of the gross area, picket as 50% and split rail as 30%. These are rough built-in allowances for how much of the fence face is actually surface; your own fence may have more or fewer gaps, so adjust the coverage or dimensions if yours differs.
What coverage per litre should I enter?
The default is 10 m² per litre, which is a placeholder. Use the figure printed on your product’s label, because coverage depends on the product and on how absorbent the timber is. The tool never lets coverage drop below 0.1 m² per litre.
Is the coverage figure per coat?
Yes. The calculator multiplies the paintable area by the number of coats and then divides by coverage, so a two-coat job needs twice the litres of a one-coat job on the same fence.
How is waste handled?
The 10% allowance is applied to the total litres, not per coat, and the can count is based on the allowance-inclusive figure. That means 3.96 litres still fits in one 4 litre can, while 4.1 litres needs two.
Does it count posts, rails and gates?
No. The area comes only from length × height. Posts, caps, gate frames and the edges of boards are not added, and rough or weathered timber that drinks more stain is not modelled either.
What does the “sides” option do?
It multiplies the gross area by 1 or 2. A fence with the same face on both sides doubles in area; the style factor then applies to the doubled figure.
Are the units imperial?
No. The tool works in metres, square metres and litres. Convert a length in feet by multiplying by 0.3048 before entering it.
Estimating stain or paint for a fence run
From fence size to litres
The estimate starts with a gross area, the run length multiplied by the height and by the number of sides you plan to coat. That gross figure is then scaled by a style factor to reflect open fences, divided by the coverage per litre you supply and multiplied by the number of coats. The result is padded by 10% to cover spillage and brush loss, then rounded up to whole 4 litre cans. Because every step is a multiplication or a division, you can rerun the numbers by changing one input at a time, for example to see how a lower-coverage stain or a third side of fence changes the can count before you commit to a product.
Style factors in the code
The table lists the three fence styles the calculator offers and the share of the gross area each one keeps. They are fixed allowances inside the tool.
| Fence style | Share of gross area | Gross vs paintable in the runs below |
|---|---|---|
| Solid board / paling | 100% | 20 m × 1.8 m, one side: 36.0 m² gross, 36.0 m² paintable |
| Picket (about half open) | 50% | 30 m × 1.2 m, two sides: 72.0 m² gross, 36.0 m² paintable |
| Split rail (about 30% coverage) | 30% | 12 m × 1.5 m, one side: 18.0 m² gross, 5.4 m² paintable |
Four fences, as the calculator returned them
These runs use fixed inputs. The first has a solid face on one side with a single coat, the second repeats the default settings with two coats, the third is a picket fence coated on both sides, and the fourth is a split rail.
| Job | Paintable area | Litres | With 10% waste | 4 L cans |
|---|---|---|---|---|
| 20 m × 1.8 m, solid, 1 side, 1 coat, 10 m²/L | 36.0 m² | 3.6 L | 4.0 L | 1 |
| 20 m × 1.8 m, solid, 1 side, 2 coats, 10 m²/L | 36.0 m² | 7.2 L | 7.9 L | 2 |
| 30 m × 1.2 m, picket, 2 sides, 2 coats, 8 m²/L | 36.0 m² | 9.0 L | 9.9 L | 3 |
| 12 m × 1.5 m, split rail, 1 side, 1 coat, 10 m²/L | 5.4 m² | 0.5 L | 0.6 L | 1 |
Why the second coat matters most
The first two rows differ only in the number of coats, yet the can count doubles from one to two. The picket fence shows a different effect: its gross area is 72 m², twice the paintable area, because the style factor halves the surface to be coated even though the fence is coated on both sides. Check that your fence really matches the 50% assumption; a close-boarded fence with decorative gaps is nearer to the solid setting.
What to verify before buying
Read the label for the coverage rate and for the number of coats the product asks for, then enter both. Rough-sawn or weathered boards absorb more, which lowers real coverage, and the tool has no adjustment for that. If you are close to a can boundary, buy the larger quantity so the batch of stain matches across the whole fence. Keep the receipt for any unopened cans in case your measurements were slightly generous.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →