Calculate how much stain you need, adjusting for the surface roughness and number of coats.
Usage Tip
Stir stain often and never shake it; pigment settles, and a quick wipe of the excess gives a more even tone.
Rough-sawn and weathered wood use more than smooth, planed stock.
How Much Stain Do I Need?
Find the surface area, pick the stain type and wood texture, and divide by the coverage rate. Smooth, new wood with a semi-transparent stain runs about 250-400 sq ft per gallon; rough-sawn or weathered wood and solid stains cover far less. Most exterior stains are one coat (two on bare or thirsty wood).
Deck Stain Coverage
Decks have a horizontal walking surface plus rails, and the boards are often rough or weathered, so coverage is lower than a wall. Budget about 200-300 sq ft per gallon on smooth deck boards and 150-200 on rough or older wood. Do not forget the railings, balusters, and stair stringers – spindles in particular eat stain.
| Deck size | Area | Semi-transparent, 1 coat |
|---|---|---|
| 10 x 10 | 100 sq ft | about 1 gal |
| 12 x 16 | 192 sq ft | about 1 gal |
| 16 x 20 | 320 sq ft | about 1-2 gal |
| 20 x 20 | 400 sq ft | about 2 gal |
Fence Stain Coverage
Fence area is length times height, times the number of sides you are staining. Rough-sawn pickets and end grain drink stain – figure 100-175 sq ft per gallon for rough fencing. A 100 ft run of 6 ft fence is 600 sq ft per side; both sides is 1,200 sq ft, roughly 6-8 gallons on rough wood.
Stain Types & Opacity
| Type | Notes |
|---|---|
| Oil-based semi-transparent | Penetrates, shows grain; easy to recoat |
| Water-based | Low odor, fast dry, durable; raises grain |
| Solid / opaque | Hides grain like paint; covers less area |
| Gel | Thick, for vertical and furniture; low coverage |
| Deck & fence | Formulated for foot traffic and UV |
Opacity drives coverage and looks: clear and semi-transparent show the most grain and cover the most area; solid hides grain and covers less but lasts longer on worn wood.
Coverage by Wood Texture
| Surface | Coverage adjustment |
|---|---|
| Smooth, planed | full rate (x1.0) |
| Rough-sawn | about 40% less (x0.6) |
| Weathered / dry | about 20-25% less (x0.8) |
Surface Prep & Sanding
- Clean the wood – strip old finish, wash off dirt and mildew, rinse.
- For decks, use a deck cleaner/brightener and let dry fully.
- Sand smooth wood to 80-120 grit so it accepts stain evenly; do not over-sand or it will not absorb.
- Rough-sawn wood usually needs no sanding – just clean.
- Spot-test on a hidden area to confirm color and absorption.
Drying & Recoat Time
| Stain | Recoat | Foot traffic |
|---|---|---|
| Oil-based | after 12-24 hours | 24-48 hours |
| Water-based | after 2-4 hours | 24 hours |
Weather, Moisture & UV
Exterior stains break down under UV – semi-transparent finishes need recoating every 1-3 years, solids last longer. Darker pigments and quality UV blockers extend the life on sun-exposed decks and fences.
Frequently Asked Questions
How much stain do I need for a deck?
About 1 gallon per 200-300 sq ft of smooth deck, less on rough or weathered boards. Add for railings and spindles. Enter your deck above.
How much stain for a fence?
Length times height times sides; rough fencing covers only 100-175 sq ft per gallon, so a 100 ft both-sides fence can take 6-8 gallons.
One coat or two?
Most semi-transparent stains are one coat; bare, rough, or thirsty wood may take two. Solid stains often want two.
Why does rough wood use so much more?
Rough-sawn and weathered wood has more surface area and open pores, soaking up far more stain than smooth, sealed boards.
Do I sand before staining?
Sand smooth lumber to 80-120 grit for even uptake; rough-sawn usually just needs cleaning.
Can I stain wet wood?
No – let it dry to about 15% moisture or less, or the finish will not penetrate and may peel.
Related Calculators
Note: stain coverage figures are approximations and vary widely with stain type and opacity, wood species, texture, age, moisture, and application. Rough, porous, and weathered wood uses much more – always check the product label, spot-test, and buy extra. General DIY guidance, not a professional estimate.