Deck Stain Calculator
Estimate gallons of stain or sealer for a deck.
Enter your deck dimensions, the number of coats, and your stain's coverage to estimate the gallons needed. Add extra for railings, stairs, and the gaps between boards, which all drink up more stain than flat math suggests.
How it works
Gallons = deck area × coats ÷ coverage. Deck stains cover roughly 150–300 square feet per gallon depending on the wood's porosity and texture — rough or weathered boards absorb far more than smooth, sealed ones.
Frequently asked questions
How much deck stain do I need?
Multiply deck area by coats and divide by the coverage (about 250 sq ft per gallon). A 16×12 deck with two coats needs roughly 1.5 gallons, plus extra for railings.
How much does a gallon of deck stain cover?
Around 150–300 square feet, depending on wood porosity. Rough or weathered boards absorb much more than smooth ones.
Should I stain railings separately?
Yes — railings, balusters, and stairs add significant surface area. Add 10–20% or measure them on their own.
Is this calculator free and private?
Yes. Every CubicCabin calculator runs entirely in your browser, so the numbers you enter are never uploaded or stored. There's no sign-up, no limits, and it keeps working even if you lose connection after the page loads.