Deck Stain Calculator
Buying the right amount of deck stain means no mid-project trips to the store and no leftover gallons gathering dust. Enter your deck dimensions, pick your stain type, and set the number of coats to find out exactly how many gallons to buy.
Stain Types and Coverage Rates
Different stain types cover different amounts per gallon because of their solids content and how deeply they penetrate the wood:
| Stain Type | Coverage (ft²/gal) | Best For |
|---|---|---|
| Transparent/clear | 250-350 | New wood, showing grain |
| Semi-transparent | 200-300 | Most decks, some color |
| Solid/opaque | 150-250 | Weathered wood, full coverage |
| Penetrating oil | 100-200 | Hardwoods, deep protection |
How Many Coats?
- New wood: 2 coats of semi-transparent or transparent stain
- Previously stained: 1-2 coats, depending on wear
- Solid stain on weathered wood: 2 coats for even coverage
- Oil-based penetrating: Often 1 coat is enough since the wood absorbs what it needs
Do Not Forget the Railings
Railings have a lot of surface area because of all the balusters, posts, and top rails. A typical railing adds about 3 ft² of stainable surface per linear foot. For a 12 x 16 ft deck with railing on 3 sides, that is roughly 132 extra square feet.
Prep Makes the Difference
Stain coverage rates assume clean, dry wood. If your deck has old stain, mildew, or dirt, you will get significantly less coverage per gallon. Always pressure wash and let the wood dry for 24-48 hours before staining.