DECK STAIN
DECK STAIN
gal = ft² ÷ 200
ft
ft
ft
RESULT
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New/smooth wood: ~250 ft²/gal. Weathered: ~150 ft²/gal. Always do 2 coats for new applications.
About this calculator
This deck stain calculator tells you how many gallons of stain or sealer you need for a deck. Coverage depends on the wood condition: weathered or rough wood absorbs more (150 ft²/gal), while smooth or previously sealed wood gets full coverage (250 ft²/gal). The calculator includes deck surface plus railing area, which is often forgotten and accounts for 15–25% of total stain.
Common questions
How often should I re-stain my deck?
Every 2–3 years for transparent or semi-transparent stains; every 4–6 years for solid (paint-like) stains. South-facing decks fade faster. Sign you need a refresh: water no longer beads on the surface and the wood looks gray.
Should I use stain or sealer?
Both at once is ideal — most modern products are stain + sealer combined. Pure sealer (clear) protects from water but lets the wood gray over time. Stain (with pigment) blocks UV, preserves color, and is what you want for visible decks.
Can I stain a brand new pressure-treated deck?
Wait 3–6 months. Fresh PT lumber is too wet — stain won't soak in. Test with water: if it beads, wait longer. If it absorbs in seconds, you're ready. Some KDAT (kiln-dried after treatment) lumber can be stained in days.