Wood Finish Coverage Calculator
Estimate how much finish to buy for a woodworking project. Enter the surface area in square feet, how many coats you plan, and the finish type to see the gallons and quarts you need.
How to calculate finish coverage
- Enter the total surface area to finish in square feet.
- Choose the number of coats and the finish type.
- Read the gallons and quarts required, then round up to the can sizes sold.
Examples
120 sq ft, 2 coats of polyurethane
Area 120 sq ft, 2 coats, polyurethane (400 sq ft/gal)
240 sq ft covered, 0.6 gallons (2.4 quarts)
Frequently asked questions
How much stain do I need?
Multiply the surface area by the number of coats, then divide by the coverage per gallon. For 200 square feet at two coats of stain rated 200 square feet per gallon you need about 2 gallons.
How many square feet does a gallon cover?
It depends on the finish. As a rough guide, stain covers about 200, paint about 350, polyurethane about 400 and Danish oil about 150 square feet per gallon for one coat.
Why does coverage drop on bare or porous wood?
Unsealed and open-grain woods soak up the first coat, so real coverage on the initial coat is often lower than the figure on the can. Buy a little extra for the first coat.
Should I round up when buying?
Yes. Finish is sold in fixed can sizes such as quarts and gallons, so round the result up to the next size and keep a little spare for touch ups.
Does this include the second side and edges?
Only if you included them in the surface area. For boards finished on both faces, count both sides and the edges when you measure the area.
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