Deck Stain Calculator
Gallons for one or two coats — before you're halfway done and a can short.
Your deck
Materials list
Generated by AllUnits.io — allunits.io/calculators/deck-stain
How this calculator figures it
Coverage uses the published range for exterior deck stains — 150 to 300 square feet per gallon on a first coat over bare wood, with second coats stretching about 50% further since the surface is partially sealed. Rough, weathered boards drink more; the number printed on your can for your product governs.
How it works
Deck area is length × width, plus about 5 square feet per linear foot of railing (both sides — a rough allowance). Worked example — a 16 × 12 ft deck at 200 sq ft/gal, two coats: 192 ÷ 200 + 192 ÷ 300 = 0.96 + 0.64 = 1.60 gallons computed — buy 2 gallons, or 1 gallon plus 3 quarts if your product sells quarts.
Deck stain FAQs
How far does a gallon of stain go?
150–300 sq ft on the first coat depending on product and wood condition; second coats reach 250–400 because the wood is partly sealed.
One coat or two?
Follow the can — most semi-transparent products call for one or two THIN coats. A thick coat peels.
Can I stain new pressure-treated wood right away?
Let it dry until water soaks in instead of beading — often several weeks. General practice.
Does a sprayer use more stain?
Yes — plan roughly 10–20% extra. Rough allowance.
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Related calculators & sources
Building or re-boarding the deck first? Count the boards with the Deck Board Calculator, and lay out the steps with the Stair Calculator. Coverage rates come from published stain-coverage data; convert measurements with the area and volume converters.
Estimates for planning and purchasing. Not engineering or code-compliance advice — confirm structural work with your local building department.