Sealer Cost CalculatorSealer & Finish Cost Calculator
Calculate how much sealer, lacquer or finish a job needs and what it costs. Account for coats, coverage rate, pack size and wastage to order the right quantity and price your finishing accurately.
Why this calculation matters
Coverage decides how much to buy and from which batch. Sealer batches vary in tint enough to show across a large surface, so ordering short is not just a cost problem.
Sealer Cost Calculator
Sealer & Finish Cost Calculator
From product datasheet, per coat.
Overspray, absorption, touch-ups.
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About Sealer Cost Calculator
Sealers, primers, lacquers and finishes are priced by the litre but applied by area, coat by coat. This calculator works out exactly how much product a job needs - factoring in the number of coats, the product's coverage rate and a realistic wastage allowance - then converts that into packs to buy and a total and per-square-metre cost for accurate quoting. It estimates deck sealer quantity from your area and coats, using realistic wood sealer coverage per litre figures.
Where Is This Used?
Formulas Used
Total area = Surface area x Number of coatsLitres needed = (Total area / Coverage rate) x (1 + loss%)Packs = ceil(Litres needed / Pack size)Total cost = Packs x Price per packCost per m2 = Total cost / Surface areaHow the calculation works
Coverage is per coat, so two coats need twice the material before any allowance for overspray or absorption. End grain and porous substrates drink far more than the flat rate suggests.
Show the formula
Total area = area x number of coats. Litres = total area / coverage rate x (1 + application loss). Packs = ceiling(litres / pack size). Cost per square metre = total cost / area.Manufacturer coverage rates assume a prepared, sealed substrate. Buy from one batch: tint varies between batches and shows as a band across a large surface.
References
No external standard governs this calculation — it is arithmetic from your inputs. Take product-dependent figures from the manufacturer data sheet, not from here.
Limitations of this calculation
Estimates quantity from surface area and coverage rate. It does not account for end-grain absorption, substrate porosity, application method losses, overspray, or tint variation between batches.
Do not use this for Firm quotation without a site measure and a manufacturer coverage figure.
Figures are engineering estimates from the inputs and assumptions shown. Verify against the actual material and, where the result affects structure or safety, against a qualified professional.
- Coverage-rate method: litres = area × coats ÷ coverage × (1 + loss)
Formula checked against the sources above by an automated regression test (tests/verify-phase2.js) that derives each expected value independently of this page. Last reviewed .
How to use this tool
- Enter the trade details below, then press Calculate.
- Fill in area, number of coats, coverage rate, pack size.
- Press Calculate.
Worked example
Common mistakes to avoid
- Counting only one coat. End-grain sealer and most finishes need two or more coats, which doubles the material.
- Using the can's ideal coverage rate. Rough or thirsty wood drinks far more than the label says.
- Forgetting wastage in the tray, brush and overspray. Add at least 10%.
Frequently Asked Questions
Wood species data
Density, hardness and movement for 60 timbers