Stain Calculator
Enter your deck or fence dimensions. We'll size the stain order — wood is more porous than walls, so coverage is way lower than paint.
Advanced options
- Total area
- 0 sq ft
- With waste factor
- 0 sq ft
- Coverage used
- 0 sq ft/gallon
- Estimated cost
- —
How the stain calculator works
Wood is way more porous than drywall, so stain coverage is roughly half of paint. We compute the area, multiply by coats, divide by coverage, add a waste factor, and round up to whole containers.
Coverage by surface
- Smooth (planed) wood — 250–350 sq ft / gallon (~6–8 m²/L). Recently milled lumber, freshly sanded decks.
- Average — 150–250 sq ft / gallon (~4–6 m²/L). Default for most projects.
- Rough / weathered — 100–150 sq ft / gallon (~2.5–4 m²/L). Old fences, rough-sawn cedar, heavily weathered.
- First coat on bare wood — even rougher absorption; budget +20% for it specifically.
Stain types — pick by use
- Transparent / clear sealer — lets full grain show. Lowest UV protection. Re-coat every 1–2 years. Best for new high-quality wood you want to showcase.
- Semi-transparent — adds a tint while showing grain. Mid UV protection. Re-coat every 2–3 years. Standard for decks.
- Semi-solid — partial pigmentation, hides minor flaws. Re-coat every 3–5 years. Good for older decks where you want some grain still visible.
- Solid stain — opaque, looks like paint but soaks in. Hides everything. Re-coat every 4–7 years. Best for older fences or decks past their prime.
Common questions
Do I need to strip old stain first?
If the old stain is still bonded and the same product family (transparent over transparent, solid over solid), no — clean and re-coat. If you're going from solid to transparent, yes, you'll need to strip. Going darker or to solid? Just clean and apply.
Should I stain the underside of deck boards?
Most pros say yes for new decks (it slows moisture cycling and warping), but it's optional. If you do, add 80–100% to the area depending on access. Not worth it for older decks already installed.
Oil-based or water-based?
Oil-based penetrates deeper and lasts longer between coats but VOCs are higher and cleanup is messier. Water-based dries faster, has lower VOCs, and modern formulas are nearly as durable. For DIY, water-based is usually the better choice.
For exterior walls (siding) use the paint calculator with a 250 sq ft / gal coverage assumption.