How much paint will you actually need? Enter room dimensions, subtract doors and windows, choose coats and coverage, and see a transparent estimate.
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Planning estimate — not a final quote
Wall area is the room perimeter (twice the length plus twice the width) multiplied by wall height. Subtract the combined area of windows and doors and add the ceiling only if you plan to paint it. The result is the net surface area. Measure irregular walls individually, and do not subtract openings that are already excluded from your wall measurements.
Multiply the paintable area by the number of coats and divide by the coverage listed on your specific paint tin in square metres per litre, per coat. The calculator adds a selectable waste allowance for rollers, trays and touch-ups. Coverage varies with surface texture, absorption, colour changes and application technique, so it is a planning estimate rather than a product guarantee.
Fresh plaster, porous timber, patched surfaces and dramatic colour changes may require primer or an additional coat. Primer is a separate product with its own coverage. Keep a small amount of matching paint for touch-ups and check the exact batch, sheen and manufacturer recommendations before purchasing.
A 4 × 3 m room with 2.5 m walls has 35 m² of gross wall area. After subtracting 4 m² of openings, 31 m² remains. With two coats, coverage of 10 m² per litre and 10% allowance, the estimate is 6.82 litres for walls, before rounding to available tin sizes.
Only when the ceiling option is enabled.
No, primer should be estimated separately using its own product label.