How to Calculate Fence Stain
Stain coverage depends on two things: the total surface area of your fence and how absorbent the wood is. Calculate surface area by multiplying length by height — then multiply by 2 if staining both sides. Apply the coverage rate for your wood type to get gallons needed per coat.
Stain formulaSq Ft = Length × Height × 2 (both sides)
Gallons per coat = Sq Ft ÷ Coverage Rate
Total = Gallons per coat × Number of Coats
Gallons per coat = Sq Ft ÷ Coverage Rate
Total = Gallons per coat × Number of Coats
Coverage rates differ significantly by wood condition. Rough-sawn or pressure-treated lumber absorbs more stain than smooth planed wood. Weathered, grey wood is the most porous and requires the most stain — and typically needs a cleaner and brightener applied before staining to open the wood grain and ensure even absorption.
Coverage Rates by Wood Type
- Rough / pressure-treated wood — 100 to 150 sq ft per gallon. New fence lumber typically needs 2 coats to seal properly.
- Smooth / planed wood — 200 to 250 sq ft per gallon. Pre-primed or smooth-surfaced wood absorbs less product.
- Weathered / grey wood — 80 to 120 sq ft per gallon. Grey, weathered fences are highly porous and absorb significantly more stain. Always clean and brighten before staining weathered wood.
Stain Product Selection
- Semi-transparent stain — Shows wood grain. Good for new or lightly weathered wood. Easier to recoat without stripping.
- Solid stain — Hides grain, like paint but more flexible. Better for weathered or damaged wood. More durable in high UV climates but harder to strip when recoating later.
- Clear sealer — Preserves natural wood look. Requires reapplication every 1–2 years and provides minimal UV protection.
- For pressure-treated wood, wait 3–6 months after installation before staining to allow the preservative to dry and the wood to stabilize.