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Wood Stain Calculator

Calculate how much stain you need for a deck, fence or wood siding project.

Result

Stain Needed
4 gal (15.1 L)

Stain coverage per gallon is lower than paint (typically 150-300 sq ft vs. 350+ for paint) since it soaks into the wood rather than forming a surface film - rough-sawn or weathered wood absorbs even more.

About the Wood Stain Calculator

Stain soaks into wood rather than forming a surface film the way paint does, which is part of why it covers noticeably less area per gallon and needs its own separate coverage math.

How It Works

The calculator multiplies your surface area by the number of coats, then divides by the stain's coverage rating per gallon to estimate total gallons needed.

gallons = (surface area × coats) ÷ coverage per gallon

Examples

A standard deck

400 sq ft of decking with 2 coats at 200 sq ft coverage per gallon needs about 4 gallons of stain.

A fence with rough-sawn lumber

The same 400 sq ft area on rough-sawn fence boards, absorbing more stain, might need coverage closer to 150 sq ft per gallon, pushing the total up to about 5.3 gallons.

Advantages

  • Accounts for multiple coats instead of assuming a single application
  • Shows results in both gallons and liters
  • Adjustable coverage figure to match the specific stain type and wood surface

Common Mistakes

  • Using a paint-level coverage rate when estimating stain, which runs lower per gallon
  • Not adjusting coverage downward for rough-sawn or highly absorbent wood
  • Buying for a single coat on a project that calls for two

Edge Cases to Watch For

  • Stain coverage runs lower than paint, typically 150-300 sq ft per gallon versus 350+ for paint, since it's absorbed into the wood rather than sitting on top.
  • Rough-sawn, weathered, or previously unfinished wood absorbs noticeably more stain than smooth, previously sealed lumber, which can push actual coverage well below the can's stated rating.
  • Solid stains behave more like thin paint with a higher, more paint-like coverage rate, while transparent and semi-transparent stains penetrate deeper and cover less area per gallon.

Common Use Cases

  • Estimating stain needed for a deck, fence, or wood siding project
  • Budgeting a DIY wood staining project before purchasing
  • Comparing material needs between solid and semi-transparent stain products
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

How is staining a deck different from painting it?

Stain penetrates the wood fibers and lets the grain show through, while paint forms an opaque film on top - stain generally needs reapplication more often (every 1-3 years depending on traffic and exposure) but doesn't peel or chip the way paint can.

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Conclusion

Coverage per gallon runs lower for stain than paint because the wood itself absorbs much of the first coat, and rough or weathered surfaces absorb even more. Check the coverage rating for the specific stain type being used, since solid, semi-transparent, and transparent products all behave differently on the same wood.