Deck Stain Calculator
Estimate the gallons of stain or sealer needed to finish a deck's top surface.
Calculator
| Gallons (exact) | 0.58 gal |
|---|---|
| Deck surface | 144 ft² |
How it is calculated
12 × 12 = 144 sq ft. At about 250 sq ft per gallon for 1 coat: 0.58 gallons.
About this calculator
A gallon of deck stain typically covers somewhere between 150 and 300 square feet, depending on the product and how rough or weathered the wood is. The calculator uses 250 square feet per gallon per coat.
New wood, old wood and different stain types behave differently. Always check the can for coverage, the number of coats and the drying times for the product you choose.
Worked examples
| Project | Gallons to buy (whole) | Rough cost |
|---|---|---|
| a 12x12 ft deck, one coat of stain | 1 gal | $30.00 – $70.00 |
| a 16x20 ft deck, one coat of stain | 2 gal | $60.00 – $140 |
| a 12x12 ft deck, one coat of stain | 2 gal | $60.00 – $140 |
| a 20x24 ft deck, one coat of stain | 4 gal | $120 – $280 |
Buying notes
- Add the area of railings and stairs if you will stain them too.
- Clean the deck and let it dry before staining.
- Test a small area first to check the color.
Quick answers by size
Click a size for the exact quantity and cost.
How to measure and use this calculator
- Measure the deck area, plus railings and stairs if you will stain them.
- Enter the number of coats.
- Read the gallons to buy.
- Check the can: coverage varies with product and wood condition.
Common mistakes
- Staining wet or freshly power-washed wood before it dries.
- Forgetting that old, rough boards soak up more stain.
- Applying thick coats that peel instead of soaking in.
Tips
- Coverage drops on old, rough or weathered wood, sometimes to 150 sq ft per gallon.
- Do not forget railings and stairs, which add surface area.
- Two thin coats usually outlast one thick coat; check the product label.
Frequently asked questions
How much stain covers a deck?
A gallon typically covers 150–300 sq ft depending on the wood and product.
How much stain do I need for a 12x12 deck?
Around 0.6 gallons per coat at 250 sq ft per gallon, so one gallon covers a single coat with some left over.
Should I apply one coat or two?
It depends on the product; follow the label. Thin coats that soak in usually last better than one thick coat.