How much stain for a 400 sq ft deck?

    One gallon covers the label - but your deck soaked up half of it. Enter the surface area, wood type, coat count and container size to get the exact number of cans, total volume and cost.

    Two coats over 400 sq ft of softwood decking, at the 250 sq ft per gallon the label on a semi-transparent stain typically quotes, worked into whole containers rather than a raw volume. The count below assumes pine, spruce or fir, which is what most decks are built from and which drinks more stain than cedar or a tropical hardwood does.

    Three things move the answer more than the area does. Coverage rate is the big one: solid stain covers half as far as deck oil, so a can quoting 150 sq ft per gallon changes the total for 400 sq ft immediately. The second coat almost never costs as much as the first, because bare wood absorbs and sealed wood does not. And containers come in fixed sizes, so the gallons you need and the gallons you buy are rarely the same number. Change any of those in the form and watch which one actually moves the total.

    Parameters

    Enter data for calculations

    Select structure type - the calculator converts dimensions to area.

    Softwood absorbs more stain than the label rate. Hardwood and tropical absorb less.

    New bare wood: 2-3 coats. Annual maintenance: 1 coat.

    From the product label. Typical: oil 200-300, stain 200-400, preservative 100-150 sq ft/gal.

    Common: 1 qt (0.25 gal), 1 gal, 5 gal.

    Optional - for total cost estimate.

    Form progress0 / 5 fields

    💡 Fill in all required fields to unlock the calculate button

    The problem: stain labels lie (for your wood)

    Without a calculator

    • The label says 1 gallon covers 300 sq ft - your pine deck absorbed it in 200
    • You buy one can, run out halfway through the second coat
    • Second trip to the store - and the batch color does not match
    • No idea how wood species affects absorption

    With the calculator

    • Exact gallons adjusted for your wood species
    • Correct number of containers - no second trip
    • Multi-coat calculation built in
    • Cost estimate before you buy

    How to use this calculator - step by step

    1. Structure type - select deck, fence or other. For decks and fences, the calculator computes area from dimensions. For pergolas, gazebos or furniture, enter square footage directly.
    2. Dimensions - deck length and width in feet, or fence length and height. For fences, choose whether to stain one side or both.
    3. Wood type - softwood (pine, spruce) absorbs 15% more than the label rate. Tropical hardwoods (ipe, teak) absorb 15% less. The calculator adjusts automatically.
    4. Number of coats - new bare wood needs 2-3 coats. Annual maintenance: 1 coat.
    5. Coverage rate - from the product label (sq ft per gallon). If unknown, 250 sq ft/gal is a safe middle ground.
    6. Container size - 1 quart (0.25 gal), 1 gal or 5 gal. Larger containers cost less per gallon.
    7. Price per container - optional, for cost estimation.
    8. Read the results: total gallons, number of containers, leftover and cost.

    Coverage rates by product type

    Product type Coverage (sq ft/gal) Typical coats Best for
    Deck oil / penetrating oil 200-300 2 Decks, furniture, natural look
    Semi-transparent stain 200-400 2 Fences, siding, visible grain
    Solid stain 100-200 2 Weathered wood, color coverage
    Wood preservative / water repellent 100-150 1-2 Structural lumber, below-grade
    Clear sealant 250-350 2-3 Cedar, redwood, UV protection

    Wood absorption multipliers

    Wood type Absorption factor Effect on coverage
    Softwood (pine, spruce, fir) 1.15x Uses 15% more than label rate
    Hardwood (oak, cedar, redwood) 1.00x Matches label rate
    Tropical (ipe, teak, mahogany) 0.85x Uses 15% less - dense grain
    Composite / WPC 0.70x Uses 30% less - minimal porosity

    Practical examples

    Example 1: Pine deck 20 x 12 ft, deck oil 250 sq ft/gal, 2 coats, 1 gal cans
    Area: 240 sq ft, per coat: 1.1 gal (x1.15 softwood), total: 2.2 gal, buy: 3 cans
    Example 2: Cedar fence 100 ft x 6 ft, both sides, semi-transparent 300 sq ft/gal, 2 coats, 5 gal buckets
    Area: 1,200 sq ft, per coat: 4.0 gal, total: 8.0 gal, buy: 2 buckets
    Example 3: Ipe deck 16 x 10 ft, penetrating oil 250 sq ft/gal, 2 coats, 1 gal cans
    Area: 160 sq ft, per coat: 0.5 gal (x0.85 tropical), total: 1.1 gal, buy: 2 cans
    Example 4: Pine fence 60 ft x 4 ft, one side, preservative 100 sq ft/gal, 1 coat, 1 gal cans
    Area: 240 sq ft, per coat: 2.8 gal (x1.15), total: 2.8 gal, buy: 3 cans
    Example 5: Pergola 350 sq ft, cedar, clear sealant 300 sq ft/gal, 3 coats, 1 gal cans
    Area: 350 sq ft, per coat: 1.2 gal, total: 3.5 gal, buy: 4 cans

    FAQ - Frequently asked questions

    How many square feet does a gallon of deck stain cover?
    Most deck stains cover 200-400 sq ft per gallon on smooth, previously finished wood. On rough-sawn or bare softwood, actual coverage drops to 150-250 sq ft because the open grain absorbs more product. Always check the product label and adjust for your wood type.
    Should I buy one large container or several small ones?
    A 5-gallon bucket is typically 15-25% cheaper per gallon than individual 1-gallon cans. It also guarantees consistent color across the entire job. The downside: if you have less than 1 gallon left over, a sealed can stores better than an open bucket. For most deck projects over 200 sq ft, a 5-gallon bucket is the better value.
    Does the first coat always use more stain?
    Yes. On bare wood, the first coat soaks into the grain and coverage is 20-40% lower than the label rate. The second coat sits on top and covers closer to the rated amount. The calculator accounts for this through the wood-type absorption multiplier rather than a per-coat adjustment, which gives a reliable total.
    Can I stain composite decking?
    Most manufacturers recommend against staining capped composite boards. The cap prevents absorption, and stain will peel or wear unevenly. Uncapped composite can sometimes accept a semi-transparent stain. Always check the manufacturer warranty - staining may void it.
    How long does deck stain last?
    Penetrating oil: 1-2 years. Semi-transparent stain: 2-3 years. Solid stain: 3-5 years. South-facing surfaces and horizontal decks wear faster than vertical fences in shade. Reapply before the finish is completely worn - maintenance coats adhere better to partially intact finishes.
    What coverage rate should I use if the label does not say?
    Use 250 sq ft/gal as a safe middle estimate. This assumes a standard semi-transparent stain on smooth wood. For rough-sawn surfaces, reduce to 150-200 sq ft/gal. For thin oils on dense hardwood, increase to 300-350 sq ft/gal.

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    See also

    Deck Stain for 100 sq ft - How Many Gallons to BuyDeck Stain for 150 sq ft - How Many Gallons to BuyDeck Stain for 200 sq ft - How Many Gallons to BuyDeck Stain for 250 sq ft - How Many Gallons to BuyDeck Stain for 300 sq ft - How Many Gallons to BuyDeck Stain for 500 sq ft - How Many Gallons to BuyDeck Stain for 600 sq ft - How Many Gallons to Buy

    Calculator verified by the LiczGrupa.pl team

    Content, formulas and results have been reviewed for accuracy and relevance by our team of specialists.

    Patryk Matyjasik

    Reviewed by: Patryk Matyjasik

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