Finishing
Wood Stain Coverage Calculator with Coat Count
Estimate how many quarts/gallons of stain you need — by surface area, coats, wood porosity, and waste.
Calculator
Open / Closed / Blotch-prone
Penetrating / Gel / Dye
What makes this different
Most stain calculators assume 150–200 sq ft/qt. This one asks for the wood's porosity (open grain like oak vs closed grain like maple) and stain type (penetrating vs gel), since both change coverage by 30–50 %.
Who it's for & when to use it
Quoting a deck refinish, planning a furniture finish, ordering the right amount of dye/stain.
How to use
- Enter the dimensions of your material or the parameters of your project.
- Adjust the optional knobs (waste factor, kerf, planer allowance) to match your shop practice.
- Click Calculate and read the output. Use the per-item breakdown for ordering, the totals for budgeting.
- Compare the result to your lumber yard's quote — the effective $/BF column is the apples-to-apples number.
Formula: Coverage per coat: open-grain ≈ 125 sq ft/qt, closed-grain ≈ 175 sq ft/qt, gel ≈ 200 sq ft/qt. Total = area × coats × (1 + waste%).
Notes & tips from the shop
- Open-grain woods (oak, ash, mahogany) soak up stain; expect to apply more, or seal first with a washcoat.
- Gel stains behave like paint — they sit on top and don't penetrate. Useful for blotch-prone species like birch.
- Always test on a scrap piece before committing — color shifts dramatically with species and prep.
Frequently asked questions
Do I need a pre-stain conditioner?
On blotch-prone species (pine, cherry, birch) yes, or you'll get dark/light blotches. On oak it's optional.
How long does stain take to dry?
Oil-based: 8–24 h. Water-based: 1–2 h. Gel: 8–12 h. Always follow the can — recoating too soon causes problems.
Can I apply poly over a stain that isn't fully dry?
No. Trapped solvent causes clouding and peel. Wait the full cure time.
Limitations
Does not account for diluted stains or custom dye mixes. Coverage assumes one working pass, not back-brushed double coats.
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