Paint quantity calculator
Room dimensions or a wall area in, litres out — for as many coats as you are applying, at whatever coverage your paint actually achieves.
Litres = Paintable area ÷ Coverage × Coats
Wall area before deductions — m² · paintable — ft²
How this calculator works
- Wall area = 2 × (length + width) × height. The ceiling is length × width, added only if you tick it.
- Doors and windows are deducted as a single figure — a standard door is about 1.9 m² and a window 1.8 m².
- Litres = paintable area ÷ coverage × coats.
- Primer is calculated separately, since it usually covers slightly less per litre than a topcoat.
Coverage is the input worth getting right. Manufacturers quote a figure on the tin, but a fresh plaster surface drinks noticeably more on the first coat than a previously painted wall, and texture costs coverage too. If you are painting new plaster, budget nearer the low end of the range.
Buy a little over the calculated figure and keep the leftover sealed. Touching up later from a different batch shows.
Read the full guide: The Snag List: How Professionals Run a Final Inspection
No signal at the site? Take this calculation offline.
Every calculation a site needs — concrete, brick, steel, plaster, paint and more — in one app that works offline, in metric and imperial, anywhere in the world.
