Varnish Coverage Calculator — Quantity for Paintings
Calculate how much varnish you need for your painting based on size, varnish type and surface texture.
How We Calculate This
Varnish (ml) = Area (m²) × Coverage rate (ml/m² per coat) × Texture multiplier × Coats
Typical coverage rates (per coat)
These are heuristic studio figures, not a single manufacturer’s spec — always check your own product’s technical data sheet and use the Advanced override if it differs.
- Spray varnish: 120 ml/m² (≈8 m²/L). Spray uses the most because overspray is lost — Liquitex Professional Spray covers roughly 2 m² per 400 ml can (≈5 m²/L ≈ 200 ml/m²), Golden Archival aerosol gives ≈7–11 m²/L.
- Brush-on varnish: 80 ml/m² (≈12.5 m²/L), within the picture/wood-varnish band (Barrettine PU ≈14, Polyvine ≈15, Ronseal up to 16–20, brushed acrylic ≈6–8 m²/L).
- Retouch varnish: 60 ml/m² (≈16.7 m²/L) — applied as a thin temporary layer, so it uses the least.
Texture multipliers
Raised paint covered from all angles uses more varnish than a flat surface.
- Smooth: 1.0×
- Moderate: 1.3×
- Heavy impasto: 1.6×
Total drying time shown is the wait between coats added up (drying-per-coat × coats after the first); it excludes the final cure.
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Always verify quantities before purchasing materials.