Floor Paint Calculator — How Much Floor Paint Do I Need?

Our floor paint calculator accounts for surface porosity, which means the first coat on bare concrete or timber absorbs significantly more paint than subsequent coats.

The formula

First coat = Area ÷ (Coverage × Porosity factor)
Subsequent coats = Area ÷ Coverage × (Coats - 1)
Total paint = (First coat + Subsequent coats) × Wastage factor

Coverage rates (per coat)

• Standard floor paint: 10 m² per litre
• Garage floor paint: 8 m² per litre (conservative — named products run 9–11+ m²/L)
• Epoxy floor paint: 6 m² per litre
• Anti-slip floor paint: 6 m² per litre (aggregate-loaded, so it covers less than smooth paint)
• Floor varnish: 18 m² per litre

These are practical per-coat estimates within published UK manufacturer datasheet ranges (e.g. Watco anti-slip epoxy ≈6 m²/L, Ronseal Diamond Hard floor varnish up to 18 m²/L, Johnstone's Flortred 10–12 m²/L). Always confirm against your own tin's datasheet — actual coverage varies with surface porosity, texture and application method.

Porosity factors (first coat)

• Bare concrete: 25% more paint absorbed
• Timber: 15% more paint absorbed
• Metal / previously painted: No extra absorption