Wood Finish Coverage Calculator
How much polyurethane, stain, oil, lacquer or wood glue do I need? Pick your finish, enter your surfaces, and get the exact volume per coat, total for all coats, and the most economical can sizes to buy — metric or imperial.
Coverage calculator
Buy: –
Per-surface breakdown
| Surface | Area | Per coat |
|---|
Buy: –
Clamp 30–60 min, full cure 24 h. A thin, even film is stronger than a thick squeeze-out.
Theoretical maximum — real coverage is lower due to porosity, overspray and application loss.
Wood finish coverage reference
Typical coverage per coat from manufacturer technical data sheets and labels. Actual coverage varies with wood porosity, application method and temperature — always check your can.
| Finish | sq ft / gal | m² / L | Typical coats | Recoat / dry | Cleanup |
|---|---|---|---|---|---|
| Polyurethane — oil-based | 550 | 13.5 | 3 | 4–6 h recoat, 24 h final | Mineral spirits |
| Polyurethane — water-based | 500 | 12.3 | 4 | 2 h recoat | Water |
| Spar urethane (exterior) | 450 | 11.0 | 3 | 4–6 h recoat | Mineral spirits |
| Nitrocellulose lacquer | 500 | 12.3 | 3 | 30 min recoat | Lacquer thinner |
| Shellac (dewaxed) | 500 | 12.3 | 3 | 1 h recoat | Denatured alcohol |
| Wood stain — oil-based | 550 | 13.5 | 1–2 | 2 h, topcoat in 4–6 h | Mineral spirits |
| Wood stain — water-based | 400 | 9.8 | 1–2 | 1–2 h recoat | Water |
| Gel stain | 300 | 7.4 | 1–2 | 6–8 h between coats | Mineral spirits |
| Deck stain — semi-transparent | 300 | 7.4 | 2 | 24 h | Water / mineral spirits |
| Exterior stain — solid | 350 | 8.6 | 2 | 24 h | Water / mineral spirits |
| Danish oil | 175 | 4.3 | 3 | 4–6 h recoat, 24 h cure | Mineral spirits |
| Tung oil (pure) | 150 | 3.7 | 3 | 24 h between coats | Mineral spirits |
| Boiled linseed oil | 250 | 6.1 | 3 | 24 h between coats | Mineral spirits |
| Teak oil | 200 | 4.9 | 2 | 8–24 h recoat | Mineral spirits |
| Osmo Polyx-Oil (hardwax) | 977 | 24.0 | 2 thin | 8–10 h recoat | Brush cleaner |
How to measure your project
- Flat panels: length × width per face. A tabletop finished top and bottom = 2 sides.
- Doors & tabletops: finish both faces to balance moisture movement and prevent warping.
- Cabinets: add up door and drawer fronts; backs of doors usually get one coat.
- Fence / deck: length × height (× 2 for both sides). Rough-sawn boards drink more — use the porous setting.
- Turnings & spindles: approximate as a cylinder: π × diameter × length.
- Always round up to the next can size — running out mid-coat leaves visible lap marks.
Methodology
Finish: volume per coat = total area × (1 + condition allowance) ÷ product coverage; total = per-coat × coats. Condition allowances: bare/porous +25%, average +10%, sealed +5%.
Buy-size optimizer: exhaustive search over standard can/bottle sizes, minimizing leftover volume plus a small per-container hassle penalty — so it recommends two 1 L cans over one 2.5 L can when that wastes less.
Wood glue coverage: volume = glue area × (1 + joint allowance) ÷ glue coverage (PVA ≈ 36 sq ft/gal ≈ 3.5 fl oz per sq ft). End-grain joints get +25%.
Film thickness: theoretical coverage = 1604 × volume-solids % ÷ dry-film-thickness (mils) in sq ft/gal, or 1000 × solids % ÷ µm in m²/L.
Coverage rates are typical values from manufacturer data sheets; your can's stated coverage always wins. Estimates only — test on a hidden spot first.
Frequently asked questions
How much polyurethane do I need for a table?
Measure the top and every side you will finish, then apply (area × coats ÷ coverage). Example: a 6×3 ft table top (18 sq ft), oil-based polyurethane at 550 sq ft per gallon, 3 coats, on previously finished wood (+10%): 18 × 1.1 ÷ 550 × 3 ≈ 0.11 gal (about 14 fl oz) — one pint can is enough. Enter your exact dimensions in the calculator above.
What is the coverage of polyurethane per gallon?
Polyurethane coverage per gallon: oil-based polyurethane typically covers 500–600 sq ft per gallon per coat (manufacturer technical data sheets), and water-based polyurethane about 500 sq ft per gallon. Real coverage drops on porous or rough wood, which is why the calculator adds a wood-condition allowance.
How many coats of polyurethane should I apply?
Three coats is the standard for oil-based polyurethane (two minimum on low-wear pieces); water-based polyurethane usually needs four because each coat is thinner. Floors and tabletops — the highest-wear surfaces — deserve the full schedule plus light sanding between coats.
How much wood stain do I need?
Wood stain coverage per gallon: oil-based wood stain covers roughly 550 sq ft per gallon per coat, water-based stain about 400, and gel stain about 300. Most stain jobs are one to two coats (stain is wiped, not built up like polyurethane). If you are asking "how much stain do I need" for your project, use area × coats ÷ coverage. Example: a 200 sq ft fence needs about 200 × 1.25 ÷ 550 ≈ 0.45 gal — buy two quarts.
How much Danish oil or tung oil do I need?
Penetrating oils go much less far than film finishes: Danish oil covers about 175 sq ft per gallon per coat and pure tung oil about 150. Both are applied in 2–3 thin coats with excess wiped off, so budget roughly three times the volume you would for polyurethane on the same area.
What is the coverage of Osmo Polyx-Oil?
Osmo Polyx-Oil covers approximately 24 m² per litre per coat (about 258 sq ft per litre) — far more than conventional finishes because it is applied extremely thin. Two thin coats are recommended; a 20 m² floor needs about 20 ÷ 24 × 2 ≈ 1.7 litres.
How much wood glue do I need per square foot?
PVA wood glue covers roughly 36 sq ft per gallon of glued surface — about 3.5 fl oz per square foot. A 24 sq ft panel glue-up needs about 24 ÷ 36 × 128 ≈ 85 fl oz plus a 10% allowance, so three 32 oz bottles. End-grain joints absorb more; the calculator adds 25% for end grain.
How long does wood glue take to set and cure?
Standard PVA wood glue (e.g. Titebond Original) needs clamping for 30–60 minutes, reaches handling strength in a few hours, and full cure in 24 hours. Do not stress the joint before 24 hours; cold or humid shops slow curing.
Does bare or porous wood need more finish?
Yes. Bare, rough-sawn or porous wood (oak, ash, pine end grain) can drink 25% more finish on the first coat than sealed wood. The calculator's wood-condition setting adds 25% for bare/porous wood, 10% for average previously finished wood, and 5% for sealed surfaces (application loss always remains).
Should I count both sides and the edges of a board?
Yes — finish both faces and all edges to slow moisture exchange and prevent warping, especially on tabletops and doors. Add each face as a surface row with its side count, or use the presets (door = both sides) above.
How much wood finish do I need per square metre?
Divide your area in m² by the product's m²-per-litre rate: oil-based polyurethane ≈ 13.5 m²/L, water-based ≈ 12.3, oil stain ≈ 13.5, Danish oil ≈ 4.3, tung oil ≈ 3.7, Osmo Polyx-Oil ≈ 24. Switch the calculator to metric mode and all rates, areas and can sizes convert automatically.
What size cans should I buy — one big can or several small ones?
Buy the combination with the least leftover: the optimizer compares every mix of standard can sizes and picks the lowest-waste option. Example: needing 1.83 L, two 1-litre cans (2.0 L) beat one 2.5 L can (0.67 L wasted). Small cans also stay fresher once opened.
How is finish coverage related to film thickness?
Theoretical coverage = 1604 × volume-solids % ÷ dry-film-thickness in mils (sq ft per gallon), or 1000 × solids % ÷ thickness in microns (m² per litre). A 55%-solids polyurethane at 1.5 mils covers about 588 sq ft/gal — matching manufacturer data. Use the film-thickness tab above to convert.
Do Minwax and Varathane have the same coverage?
Roughly, yes: most consumer oil-based polyurethanes cluster around 500–600 sq ft per gallon and stains around 500–600, because the chemistry (solids content) is similar. Always check the coverage printed on your specific can — it overrides any calculator default.
Can I use this calculator for fence and deck stain?
Yes. Choose a deck/fence stain product, set the wood condition to bare/porous, and add each fence run as a surface row (length × height × sides). A 10-panel 6×8 ft fence, both sides, in semi-transparent deck stain (300 sq ft/gal, 2 coats) needs about 8 gallons.
Is my project data private?
Yes. This calculator runs 100% in your browser — your dimensions, product choices and prices are never sent to any server.