Bedroom 4 x 3 m, walls only, 2 coats
- Input
- 4 x 3 x 2,7 m, 1 porta, 1 janela, 9,4 m²/L, 10%
- Expected output
- 34,2 m², 8,0 L: 2 x 3,6 L + 1 x 0,9 L (R$ 178)
The combination exceeds the 8.004 L by only 0.096 L.
Carregando ferramenta… / Loading tool…
how much paint do I need for a room
On the Rooms tab enter length, width, ceiling height, doors and windows; on the Paint tab adjust coats and coverage. The result gives the liters and the best mix of cans, priced from your own table.
The combination exceeds the 8.004 L by only 0.096 L.
That is 46.2 m² x 2 coats ÷ 9.4, plus 10%.
It leaves 6 L, but the big can still costs less than four 3.6 L cans.
The sealer uses its own prices and cans.
Higher coverage cuts the liters, but real coverage is the one on the can.
Take the net wall area, multiply by the coats and divide by the coverage. A 4 x 3 m bedroom with a 2.7 m ceiling, one door (1.6 m²) and one window (2.0 m²) has 14 x 2.7 = 37.8 m² gross and 34.2 m² net. With 2 coats at 9.4 m²/L that is 7.3 L, and 8.0 L with a 10% margin. The best purchase at the example prices is two 3.6 L cans plus one 0.9 L can, or 8.1 L. The coverage printed on your own paint can always beats the default value.
Deducting gives the area actually painted and avoids buying extra paint. The calculator uses 1.6 m² per door and 2.0 m² per window, both editable, and lets you switch the deduction off if you prefer a more generous count.
Two coats is the starting point for acrylic paint on a sealed wall. Dark colors over light ones, stained walls or textured walls can call for three; the calculator accepts 1 to 6 coats.
Because the price per liter usually drops with the package. At the example prices, 18 L costs R$ 15.56 per liter and 3.6 L costs R$ 20.83. With the Least leftover goal you trade cost for less idle paint.
They are examples from October 2026, not quotes. Edit the price of each can to match your store and the cost and combination are redone on the spot.
Floor 20 m², walls 43 m² (openings deducted: 5.6 m²)
Floor 10.5 m², walls 31.5 m² (openings deducted: 3.6 m²)
A door of 0.80 x 2.00 m is 1.6 m² and a window of 1.00 x 2.00 m is 2.0 m². Edit them to match your job. With the deduction off, the numbers are more generous.
Estimated total: R$3,789.00 across 6 items.
Estimates for budgeting. Structure (slabs, beams, columns, foundations) needs an engineer and ART.