Wood Finish Coverage Calculator
Calculate how much wood finish, stain, varnish, or oil you need for any project.
Avoid running out mid-coat or buying too much.
Calculating finish coverage before you start a project saves you from the worst woodworking outcome — running out of finish mid-coat and having to hunt for a matching product while your project dries unevenly.
Formula: Volume needed = Surface area / Coverage rate × Number of coats
Typical coverage rates for common wood finishes:
| Finish type | Coverage per litre |
|---|---|
| Danish oil / tung oil | 10–15 m² |
| Linseed oil | 8–12 m² |
| Wipe-on polyurethane | 12–16 m² |
| Brush-on polyurethane | 14–18 m² |
| Lacquer (spray) | 10–14 m² |
| Shellac (2 lb cut) | 12–16 m² |
| Water-based stain | 10–15 m² |
| Oil-based stain | 12–16 m² |
| Hard wax oil | 20–25 m² |
Factors that reduce coverage:
- Grain porosity: Open-grained woods (oak, ash, mahogany) absorb more finish than closed-grain woods (maple, cherry, birch). Add 20–30% for open-grain species.
- End grain: End grain absorbs 3–5× more finish than face grain. A pre-seal coat or extra sanding helps.
- Surface roughness: Rough-sawn wood absorbs more than planed and sanded surfaces.
- Temperature: Cold finish is thicker and covers less area. Thin by 5–10% in cold conditions.
Number of coats: Most finishes require 2–3 coats. Oil finishes often need 4–6 for full protection. Always follow manufacturer recommendations and sand lightly (320-grit) between coats for adhesion.
Buy 15–20% more than calculated to account for waste, spills, and touch-ups.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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