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.