Deck stain calculator
Measure the deck floor, railing and stairs, pick your stain type, and see how many gallons to buy for the coats you plan.
Estimates round up. Check product labels and supplier figures before ordering.
Deck stain coverage per gallon
| Stain type | Rough or weathered wood | Smooth wood |
|---|---|---|
| Transparent or toner | about 250-350 sq ft/gal | about 400-600 sq ft/gal |
| Semi-transparent | about 200-300 sq ft/gal | about 400-500 sq ft/gal |
| Solid color | about 200-300 sq ft/gal | about 400-500 sq ft/gal |
How it's calculated
The calculator adds up three surfaces, divides by your stain's coverage per gallon, and multiplies by the number of coats.
Floor = length (ft) x width (ft)
Railing = railing length (ft) x railing height (ft) x 2 sides
Stairs = steps x about 5 sq ft
Gallons = (floor + railing + stairs) / coverage per gallon x coats
Example: a 16 x 12 ft deck is 192 sq ft. Add 40 ft of 3 ft railing (240 sq ft for both sides) and 4 steps (20 sq ft) for 452 sq ft. Semi-transparent stain at about 250 sq ft per gallon needs 1.81 gallons per coat, or about 3.6 gallons for two coats.
Coverage figures follow manufacturer ranges for rough or weathered surfaces, which soak up more stain than smooth new boards. Railing balusters have four faces, so treating the railing as two solid sides is a rough but practical estimate. The 5 sq ft per step allows for the tread, riser and stringer faces of a typical stair.
What you'll need
- Deck stain
- Deck cleaner
- Stain pad applicator
- Pump sprayer
- Deck brush
Common questions
How much does a gallon of deck stain cover?
Usually about 200 to 300 square feet on rough or weathered wood, and up to 400 to 600 square feet on smooth wood. The can lists the figure for that product.
How many coats of deck stain do I need?
Many semi-transparent and solid stains call for two coats, often applied wet-on-wet. Some penetrating oils are a single coat, so check the label.
How much stain for a 12 x 16 deck?
The floor alone is 192 square feet, so about 0.8 gallon per coat of semi-transparent stain. Railings and stairs can more than double that.
Should I buy a 5 gallon pail or 1 gallon cans?
A 5 gallon pail usually costs less per gallon once you need four or more. Buying all the stain from one batch, or mixing cans together, keeps the color even.