Enter your room dimensions for an instant estimate, including coats, openings and a sensible waste allowance.
We calculate the four walls, subtract approximately 1.9 m² per door and 1.4 m² per window, add the ceiling if selected, then account for your coats and waste allowance.
Paint = (paintable area × coats ÷ coverage) × (1 + waste %)
Coverage varies by paint, surface and application method. Check the figure printed on your paint tin and replace the default when available.
It covers small measuring differences, surface texture and paint left in trays or rollers. Reduce it for a very simple room or increase it for rough surfaces.
No. Calculate primer separately because its coverage can differ from the finish paint.
Usually, subtracting standard doors and windows is enough. For unusually large openings, reduce the room dimensions or adjust the result manually.
No. The calculation runs entirely in your browser and sends no measurements anywhere.
Measure the room’s length, width and wall height, then choose the number of coats. The calculator finds the area of all four walls, subtracts standard doors and windows, and divides that area by the paint’s coverage rate. It can also include the ceiling and a waste allowance.
The large result is the practical amount to plan for. The exact unrounded estimate appears underneath it, so you can compare the answer with the tin sizes available in your shop.
A 4 m × 3 m room with 2.4 m walls, two coats, one door, one window, 10 m²/L coverage and 10% waste needs about 6.67 L. Planning for 7 L gives a small buffer.
This calculator is a planning aid, not a guarantee. Surface condition, application method and paint formulation affect real coverage.