WoodCalcs.uk
Varnish Coverage Calculator — Wood Varnish Quantities
Calculate varnish quantities for floors, furniture, and woodwork based on area and coats.
Adds 10% extra for absorption and application loss
How We Calculate This
Total coverage area = Surface area × Number of coats
Litres needed = Total area ÷ Coverage rate per litre
Oil-based polyurethane covers ~12 m²/L. Water-based covers ~14 m²/L. Always check the manufacturer's stated coverage.
Frequently Asked Questions
Apply 3-4 coats of floor varnish for good durability. Sand lightly with 220-grit between coats. The first coat can be thinned 10-20% to act as a sealer.
Marine (yacht) varnish is designed for exterior use. It contains UV filters and remains flexible to cope with wood movement. Apply at least 4-6 coats for maximum protection. Recoat annually for best results.
Oil-based polyurethane: 24 hours between coats. Water-based polyurethane: 2-4 hours. Yacht varnish: 24-48 hours. Always check dryness by touch before recoating. Lower temperatures extend drying times.
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Last updated: February 2026
All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.