How the deck stain calculator works
How much does a gallon of deck stain cover?
Most deck stain labels list somewhere between 150 and 300 square feet per gallon per coat. Smooth, new or previously sealed wood is at the high end; rough-sawn, weathered or very dry boards soak up much more. Solid stains often cover more than semi-transparent ones on the second coat.
Railings and stairs
Railings with balusters have a lot of surface: this calculator counts each foot of railing as 3 ft high on both sides, which is a reasonable planning number for spindle railings. Add stairs as extra length or area.
Tips
- Clean and let the deck dry fully before staining — follow the can's dry-time requirement.
- Do a water test: if drops soak in quickly, the wood will absorb stain fast and coverage will be lower.
- Buy all stain at once so the tint matches.
Frequently asked questions
How much stain for a 12x16 deck?
The deck floor is 192 sq ft. Two coats at 200 sq ft per gallon is 1.9 gallons — buy 2 gallons, more if you also stain railings.
How many coats of deck stain?
Most semi-transparent and solid stains recommend two thin coats; some penetrating oils are one-coat products. Follow the label.
Does a 5-gallon pail make sense?
For large decks or decks with long railings, a 5-gallon pail is often cheaper per gallon and keeps the color consistent.