Choose deck or fence, enter the size, and set the coverage and number of coats. The calculator tells you how many gallons of stain or paint to buy, and which can sizes.
Cost
Coverage depends on the product and the wood. Rough, weathered or new wood soaks up more. Check the coverage printed on the can.
How much stain do I need?
- Gallons = area to stain × number of coats ÷ coverage per gallon
- Deck area = length × width, plus railings: railing length × height × 2 for both sides
- Fence area = length × height, times 2 if you’re doing both sides
Worked examples
- A 16 × 12 ft deck, 2 coats at 200 sq ft per gallon: 192 × 2 ÷ 200 = 1.9 gallons, so 2 one-gallon cans.
- The same deck with 40 ft of 3 ft railing: 192 + 240 = 432 sq ft, so 4.3 gallons. A 5 gallon pail covers it.
- A 100 ft fence, 6 ft high, both sides, 2 coats: 1,200 sq ft, so 12 gallons: 2 five-gallon pails and 2 one-gallon cans.
Coverage per gallon
Most deck and fence stains cover somewhere between 150 and 300 square feet per gallon. The calculator starts at 200. Coverage drops a lot on:
- rough-sawn or weathered wood, which soaks up stain
- the first coat on bare wood
- balusters and spindles, which have a lot of surface for their size
Use the coverage printed on your can, and buy a little extra for touch-ups.
One coat or two?
Many semi-transparent stains recommend two thin coats on bare wood, and one coat when refreshing. Solid stains and paint usually need two. Follow the directions on the can.
Tips for a good finish
- Clean the wood and let it dry fully before staining.
- New pressure-treated lumber often needs time to dry first. A common test is to sprinkle water on it: if it soaks in, it’s ready.
- Stain in mild, dry weather, out of direct midday sun.
- Do railings and balusters first, then the deck boards, so drips don’t land on finished boards.
Frequently asked questions
How much stain do I need for a deck?
Multiply the deck area by the number of coats and divide by the coverage on the can. A 200 square foot deck with two coats at 200 square feet per gallon needs about 2 gallons.
How many square feet does a gallon of deck stain cover?
Usually 150 to 300 square feet, depending on the product and the wood.
How much stain do I need for a fence?
Multiply the fence length by the height, double it for both sides, multiply by the coats and divide by the coverage.
Should I stain both sides of a fence?
Staining both sides protects the wood evenly and looks better from both yards, but it doubles the stain.
Does this work for paint?
Yes. Enter the coverage from the paint can and the number of coats.
Results are estimates. Coverage varies with the product and the wood. See How We Calculate for the formulas we use.
Guides for this project
Decks, Stairs & FencesHow Tall Can a Fence Be? Standard Fence Heights and RulesThe standard fence height for a home is 6 feet in back and side yards and 3 to…Read the guide →8 min read
Decks, Stairs & FencesDeck Joist Spacing and Deck Board GapsMost decks use joists spaced 16 inches on center. That is the common limit for standard 5/4 wood…Read the guide →8 min read
Decks, Stairs & FencesHow Far Apart Should Fence Posts Be? Spacing and Depth by Fence TypeMost wood fence posts should be 6 to 8 feet apart, measured center to center, with 8 feet…Read the guide →8 min read