TradeCalculator.co.uk
Floor Paint Calculator — How Much Floor Paint Do I Need?
Calculate floor paint for garages, workshops, warehouses and interior concrete or wood floors. UK coverage rates.
Longest dimension of the area
Shortest dimension of the area
2 coats recommended for durability
Adds 10% for uneven surfaces and edges
10% is standard for floor painting
Recommended for bare concrete and timber
Floor primer coverage rate (default 8 m²/L)
Enter your supplier price per litre
Next up: related pages
How We Calculate This
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
Frequently Asked Questions
A standard single UK garage (roughly 5m x 2.5m = 12.5 m²) needs about 4 to 4.5 litres of garage floor paint for 2 coats on bare concrete — which is what this calculator returns for those inputs. Concrete is porous, so the first coat absorbs more; we add 25% extra paint for the first coat plus a 10% wastage allowance. A single 5L tin is usually enough for one garage.
Yes, bare or dusty concrete should be sealed first. Use a proper proprietary concrete or floor primer/sealer — or, where the manufacturer allows, a thinned first coat of the floor paint itself as directed by its datasheet. Do NOT use PVA: standard PVA re-emulsifies with moisture and sits as a non-adherent film, so the coating can peel and take the paint with it (delamination). PVA is only a temporary dust-binder, not a floor-paint primer. Previously painted concrete in good condition doesn't need priming — just clean and sand lightly.
For domestic garages, specialist garage floor paint (solvent-based) at around £25-35 per 5L is the most popular choice. For high-traffic or workshop floors, 2-pack epoxy floor paint is tougher and more chemical-resistant but costs more (£40-60 per 5L). Anti-slip paint is recommended for areas that may get wet.
Water-based floor paint: touch-dry in 2-4 hours, recoat after 6-8 hours, light foot traffic after 24 hours. Solvent-based: touch-dry 4-6 hours, recoat after 16 hours. Epoxy: touch-dry 8-12 hours, recoat after 16-24 hours. Full cure for all types: 5-7 days before heavy use or parking vehicles.
No, the concrete must be dry. Test by taping a piece of polythene to the floor overnight — if moisture appears underneath, the floor is too damp. You may need a damp-proof membrane (DPM) paint first, or wait for the floor to dry. New concrete should cure for at least 28 days before painting.
Related Calculators
Was this calculator helpful?
Last updated: June 2026
Verified against UK standards · estimates only, confirm with your supplier.