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How Much Paint for a 4 x 3.5 m Bedroom?

A 4 by 3.5 metre bedroom with 2.4 m walls, one door, one window and two coats needs about 4.7 litres of paint at 14 m² per litre, or about 5.1 litres with 10% for waste.

Try your own numbers

Room lengthRoom widthSeen from aboveDoorWindowWall heightOne wall
Key Where each paint measurement is taken.
Units
m
m
Typical ceiling. 2.4 m is common, and 2.7 m is common in newer homes. Editorial rule of thumb.
m
m²

If you fill this in, it is used instead of the room size for the walls.

Typical door. The most common internal door is 820 x 2040 mm, about 1.7 m². Taller 2340 mm doors are becoming more common in newer homes. Source: Doors Plus, listed below.
m²
Windows vary a lot. The starting figure is only a placeholder. Measure each window you will not paint.
m²
m²/L

Check the tin. The starting figure is cautious.

%
$

Adds an estimated cost for the suggested sizes.

Paintable area32.7 m²
Paint needed, 2 coats4.67 L
Paint to buy, with waste5.1 litres
Suggested tins1 × 4 L + 1 × 2 L (6 L)

Walls: 2 × (4 + 3.5) × 2.4 m = 36 m², minus doors and windows 3.3 m², gives 32.7 m² to paint. × 2 coats = 65.4 m²; ÷ 14 m²/L = 4.67 L; with 10% waste = 5.14 L.

Porous, rough or dark surfaces need more paint. Check the coverage on the tin.

Fig. 1 A 4 x 3.5 m bedroom, walls only.

Every formula is tested against worked examples. How we check

CoatsPaint to buySuggested tins
1 coat2.57 L1 × 2 L + 1 × 1 L
2 coats5.14 L1 × 4 L + 1 × 2 L
3 coats7.71 L2 × 4 L

Fig. 2 The same room at one, two and three coats.

Last checked 10/11/2026. Sources: Dulux Australia: Paint calculator (16 m² per litre for wall, trim and ceiling paint, two coats); Doors Plus: Standard internal door sizes in Australia (820 x 2040 mm is the most common).

Using the retailer’s own rate

The walls are 2 × (4 + 3.5) × 2.4 = 36 m². The door and window take off 3.3 m², leaving 32.7 m²; two coats make 65.4 m². At 14 m² per litre that is 4.67 litres.

Dulux Australia’s own calculator assumes 16 m² per litre for its wall, trim and ceiling paints, and two coats. At 16 the same room needs 4.09 litres. The page starts at 14 because real walls are rarely ideal; the number on your tin is the one to use. Rough, porous or newly plastered walls need more, and a strong colour change may need an undercoat.

Tins. The tool suggests the cheapest mix of 1, 2, 4 and 10 litre tins that covers 5.14 litres (a 4 litre and a 2 litre, giving 6 litres). Sizes vary by brand.

Common questions

Is a 4 litre tin enough?

A 4 litre tin falls short of the 4.7 litres needed for two coats at 14 m² per litre. Even at 16 m² per litre the room needs 4.09 litres, so a 4 litre tin is still just short.

Does the ceiling use the same paint?

Often not; ceilings usually take a ceiling paint. Tick the ceiling box to see the extra volume.

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