Quick planning answer
A small or medium room commonly needs roughly 6–8 litres of wall paint for two coats when the walls are smooth and previously painted. A larger living room can need around 8–10 litres. These are examples, not fixed rules: wall height, doors, windows, texture and product coverage all change the answer.
Every example below uses smooth walls at 11 m²/L per coat, deducts standard doors and windows, applies two coats and includes 10% extra for normal waste and touch-ups.
Three common room examples
| Example room | Paintable wall area | Calculated amount | Practical pack plan |
|---|---|---|---|
| Small bedroom 3 × 3 × 2.7 m 1 door, 1 window | 29.0 m² | 5.8 L | About 7 L 5 L + 2 × 1 L |
| Medium bedroom 4 × 3 × 2.7 m 1 door, 1 window | 34.4 m² | 6.9 L | About 8 L 5 L + 3 × 1 L |
| Living room 5 × 4 × 2.7 m 2 doors, 2 windows | 41.8 m² | 8.4 L | About 10 L 2 × 5 L |
The pack plan allows a little room above the calculated amount because paint is sold in fixed container sizes. Available pack sizes vary by brand and location.
How the bedroom example is calculated
For the 4 m × 3 m bedroom with 2.7 m walls, one door and one window:
- Wall area before openings: 2 × (4 + 3) × 2.7 = 37.8 m².
- Subtract a standard door and window: 37.8 − 1.9 − 1.5 = 34.4 m².
- Apply two coats: 34.4 × 2 = 68.8 m² of coating work.
- Divide by 11 m²/L: 68.8 ÷ 11 = 6.25 L.
- Add 10% extra: approximately 6.9 L.
US measurement example
A 10 ft × 10 ft room with 8 ft walls, one standard door, two standard windows and two coats has about 267 sq ft of paintable wall. At 375 sq ft per US gallon per coat, including 10% extra, it needs approximately 1.6 US gallons. A practical purchase depends on the container sizes sold locally.
Walls, ceiling and primer are separate
- Walls: the main estimate uses room perimeter and wall height, then subtracts openings.
- Ceiling: this uses room length × width. Add it in Advanced Settings only if you plan to paint it.
- Primer: useful for new, porous, repaired or stained walls and major colour changes. It is shown separately because it is usually a different product.
- Trim and doors: not included in the wall result; estimate them separately if they use another finish.
When your result may be higher
Rough or porous walls use more paint than sealed smooth walls. Deep colour changes may require primer or an extra coat. Always use the coverage and preparation instructions on the product you actually buy. Our paint coverage guide explains why coverage varies, and the measuring guide helps you collect the right dimensions.
Frequently asked questions
How much paint does a small bedroom need?
In the example above, a 3 m × 3 m room needs about 5.8 L for two coats on smooth walls. A practical preparation amount is around 6.4 L, so locally available packs may bring the purchase to 7 L.
Should I subtract doors and windows?
Yes. PaintSimple deducts 1.9 m² for each standard door and 1.5 m² for each standard window. If your openings are unusually large, divide the room into wall sections for a more exact estimate.
Is ceiling paint included?
Not by default. Open Advanced Settings in the calculator and select “Include ceiling” when needed.
Should I buy exactly the calculated amount?
No. Buy enough available packs to cover the practical range, and keep a small amount from the same batch for touch-ups.
Method and limits
These examples are generated with PaintSimple's published calculation method. The 11 m²/L smooth-wall assumption sits within the 10–12 m²/L per-coat range listed for several standard interior products by Nippon Paint Malaysia. US guidance commonly uses roughly 350–400 sq ft per gallon, as shown by Sherwin-Williams. Product specifications can change; the label always takes priority. PaintSimple is independent and is not affiliated with these manufacturers.