Paint Coverage Calculator
Work out paintable wall and ceiling area, litres of paint needed, tins to buy and total estimated cost, with editable door and window deductions.
Your results
Assumptions
- Wall area is calculated as room perimeter × wall height, before deductions for doors and windows.
- Standard door and window deductions are editable estimates — measure your own openings for accuracy.
- Spread rate and tin size vary by paint brand and surface — check the tin for the manufacturer's stated coverage.
How this calculator works
Enter your room dimensions, number of coats, spread rate, and door and window counts to see the paintable area, total area across all coats, litres required, tins to buy and estimated cost, plus any leftover paint after rounding up to full tins.
Frequently asked questions
What spread rate should I use?
Check the tin label — most interior wall paints cover roughly 10–16 m² per litre per coat, but this varies by product and surface.
Why are door and window deductions editable?
Standard sizes (1.8 m² for a door, 1.5 m² for a window) are provided as defaults, but actual openings vary, so you can adjust them for accuracy.
Does this include the ceiling?
Only if you switch on the ceiling toggle, which adds the room's floor area to the paintable total.