How much wood stain do you need? Calculate the exact gallons for your deck, fence, siding, or furniture based on stain type, wood porosity, and number of coats.
Ready to calculate
Enter your project dimensions
Last updated March 31, 2026 by our expert review team
300 sq ft
per gallon
250 sq ft
per gallon
200 sq ft
per gallon
175 sq ft
per gallon
Cherry Jane Limbago
Licensed Civil Engineer & Master Plumber
Licensed civil engineer and master plumber with 10+ years in structural design, estimation, and project management. Currently Project Engineer at Universal Robina Corporation.
See full profileHawkin
Certified Cost & Estimating Professional
AACE-certified estimator working with 20+ insulation companies including the two largest franchises in America.
See full profileUpdated March 2026
How we verify our calculatorsPer gallon on smooth wood. Rough or weathered surfaces reduce coverage 15-25%.
Shows grain, good protection
Maximum weather protection
Natural wood beauty
Paint-like coverage, durable
Preserves cedar character
Rich color, some grain visible
+15%
Higher absorption
-10%
Lower absorption
0%
Standard absorption
-25%
Minimal absorption
Always back-brush after rolling or spraying. Stain needs to be worked into the grain to penetrate evenly. Back-brush within 10 to 15 minutes of application.
Check wood moisture with a pin meter before staining. Pressure-treated lumber needs to dry below 15% MC, which takes 3 to 6 months. Staining wet PT wood causes peeling within one season.
Ready Seal requires no back-brushing and works at any temperature, making it ideal for beginners. Coverage drops to about 150 sq ft/gal on thirsty softwood.
TWP 1500 Series (oil-based) penetrates hardwoods like ipe and mahogany best. Plan for 200 to 250 sq ft/gal on dense tropical hardwoods versus the label's 300 sq ft/gal claim.
Wait 48 to 72 hours after pressure washing before staining. Use the sprinkle test: flick water on the wood, and if it beads instead of absorbing within 10 seconds, it's not ready.
Olympic Elite semi-transparent covers about 250 sq ft/gal on smooth surfaces but drops to 150 to 175 sq ft/gal on rough-sawn cedar. Calculate coverage based on actual surface texture, not the label rate.
The calculator multiplies your surface dimensions to get total square footage, then divides by the coverage rate for your selected stain type. We adjust for wood porosity. Softwoods like pine and cedar have open grain structures that absorb 15-20% more stain per square foot than dense hardwoods like oak or ipe. The result is multiplied by your number of coats and rounded up to the nearest half-gallon for practical purchasing.
In real-world conditions, label coverage rates are optimistic. Manufacturer specs assume smooth, primed surfaces at 70°F, but rough-sawn cedar fence boards can cut coverage by 30-40% compared to smooth-planed deck boards. Weathered wood that hasn't been sealed in years acts like a sponge, especially on end-grain and around fastener holes. Our absorption factor accounts for wood species, but if your project involves old, neglected wood, consider adding 10-15% to the calculator's estimate. If you need to estimate the amount of paint for interior or exterior walls, our paint calculator uses a similar coverage-based formula. The first coat always uses more stain than subsequent coats because it fills the wood pores. Expect the second coat to cover 20-25% more area per gallon.
Formula
Gallons = (Area ÷ Coverage Rate × Absorption Factor) × Coats
Example: (240 sq ft ÷ 250 sq ft/gal × 1.15) × 2 coats = 2.2 gal
Is deck stain different from fence stain?
Yes. Deck stains have more resin and UV blockers for foot traffic and standing water. Fence stains are thinner for vertical surfaces. You can use deck stain on a fence, but fence stain on a deck wears through in one season.
How often should I restain my deck?
Transparent stains last 1 to 2 years, semi-transparent 2 to 3 years, and solid stains 4 to 5 years. Splash water on the deck; if it soaks in within 30 seconds, it's time to restain.
Should I pressure wash before staining?
Yes, but keep the nozzle at 25-degree fan, stay 8 to 12 inches from the surface, and never exceed 1,500 PSI on softwood. Wait 48 to 72 hours before staining.
Which stain type should I choose?
Transparent shows full grain but lasts only 1 to 2 years. Semi-transparent balances grain visibility with 3-year durability. Solid hides the grain but lasts 4 to 5 years.
Can I stain pressure-treated wood right away?
No. New PT lumber has 40 to 60% moisture and needs 3 to 6 months to dry below 15%. Use a pin moisture meter to test before staining.
Do I need to sand before staining?
For new wood, light sanding with 80 to 100 grit removes mill glaze that repels stain. For previously stained wood, only sand if the old finish is flaking.
What's the best temperature for staining?
Apply between 50 and 90°F with no rain forecast for 24 to 48 hours. The ideal range is 60 to 75°F with low humidity. Avoid direct sunlight.
Oil-based vs water-based stain?
Oil-based penetrates deeper and lasts 20 to 30% longer, especially on hardwoods. Water-based dries faster (2 to 4 hours vs 24 to 48 hours) and has lower VOCs.
300 sq ft total | Semi-transparent, 2 coats | 2.5 gallons | ~$100
Tip: Railings have 4 exposed faces, so multiply linear footage by the combined widths, not just one side.
900 sq ft (one side) | Transparent, 1 coat | 5 gal one side / 10 gal both | ~$175-350
Tip: Rough-sawn texture cuts label coverage by 30-40%. Budget for 4.5 gal per side, not the 3 gal the label math suggests.
192 sq ft | Semi-solid, 1 coat | 1 gallon | ~$45
Tip: End-grain on post tops absorbs 3-4x more stain than face grain. Seal end grain first or budget an extra quart.
Staining in direct sunlight
Above 90°F surface temp, stain dries before penetrating and peels within weeks. Work in shade or start early morning.
Skipping the moisture meter check
New PT wood arrives at 40 to 60% moisture. Staining before it drops below 15% traps water inside, causing bubbles and peeling. A $25 pin meter pays for itself on one project.
Applying too much stain per coat
Excess stain sits on the surface and becomes sticky or flaky. Apply thin coats and back-brush excess within 15 to 20 minutes.
Not cleaning between old stain and new
Fresh stain over dirt or degraded finish won't adhere. Use a deck cleaner and stiff brush before pressure washing to break down the oxidation layer.
Mixing oil-based over water-based
Oil and water-based stains don't adhere to each other. Test with denatured alcohol: if color comes off, it's water-based. If not, it's oil-based.
Ignoring weather windows after application
Oil-based stains need 24 to 48 hours dry; water-based need 4 to 6 hours. Rain during the cure window washes out pigment and leaves blotchy areas.
Important Disclaimer
These estimates are for planning purposes only. Actual costs vary by location, material availability, and project complexity. Always get at least 3 local quotes. This calculator does not replace professional advice.