Stain coverage calculator
"How much stain do I need?" depends on surface area, substrate absorption, number of coats, and waste. The can says "150–250 sq ft per quart" — which is a uselessly wide range. This calculator gives you a real number by adjusting for your specific case.
Calculator
Why coverage is so variable
The same can of stain on a closed-grain hardwood and on end-grain can differ by 3×. End grain drinks stain; oak's pores drink stain; maple and cherry barely absorb it. The calculator's substrate picker is the biggest single factor.
After substrate, the application method matters: a brush uses less than a wiping stain; a foam brush uses less than a brush; spray uses more but wastes less to brush/roller retention.
The "box your stain" rule
Two cans of the same stain from the same brand can vary in colour slightly — pigment settles, batches differ. Always pour all cans into a single container and stir before use. This is called "boxing" and is the single biggest reason finished projects look uneven across surfaces.
Pre-seal trick for blotch-prone woods
Pine, cherry, birch and maple all "blotch" — they absorb stain unevenly. The fix is a wash coat: dilute your sealer (or shellac) 1:1 with solvent, apply as a pre-stain sealer. It blocks the pores that drink the most, evening out the colour. The calculator assumes no pre-seal; if you use one, the stain coverage goes up significantly.
Limitations
- Numbers are starting estimates. Real coverage depends on your brush, your technique and the wood's actual grain.
- Doesn't account for top-coat needs — plan a separate finish coat budget.
- Doesn't model stain recoloring after the fact — testing on scrap is mandatory.
- Spray application has different math (waste is in overspray, not brush retention).
Frequently asked questions
Can I just buy two quarts to be safe?
Yes for small projects. For a big project, mix them together in a single container (boxing) to avoid colour variation. Two un-mixed quarts can look slightly different from each other on the project.
Why does end grain drink so much more stain?
End grain is the cut end of the wood's tube-like cells. They absorb liquid like straws. To get end grain to match the rest of the piece, dilute the first coat with the stain's solvent (mineral spirits for oil-based, water for water-based), apply, dry, then apply full-strength coats.
Should I sand to a higher grit before staining?
Counter-intuitively, no. Sanding finer (e.g. 320 vs 220) closes the pores and reduces stain absorption. The colour becomes lighter. For darker stain, sand to 150–180. For lighter or more even colour, sand to 220–320 and use a pre-seal.