Paint Calculator
How much paint do I need for a room? Enter your room and find out in seconds.
Most paints cover about 10 m² per litre — check your tin.
We allow 2.0 m² per door and 1.5 m² per window. Ceilings are not included. Estimate only — check your paint tin.
Paint you need (rounded up)
That is 2 × 4-litre tins (8 litres total).
How the numbers break down
| Step | Calculation | Result |
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How it works
Wall area = 2 × (length + width) × height Paint needed = (wall area − doors − windows) × coats ÷ coverage Buy = paint needed, rounded up
Example
A room 4 m long, 3 m wide and 2.7 m high, with 1 door and 1 window, painted with 2 coats at 10 m² per litre: wall area is 37.8 m², minus 2.0 m² for the door and 1.5 m² for the window, leaving 34.3 m². For 2 coats that is 6.9 litres, so buy 7 litres — 2 × 4-litre tins.
FAQ
How much paint do I need for a room?
Multiply the wall area by the number of coats, divide by the paint coverage, and round up.
Do I need primer?
On new plaster or a big colour change, yes. Primer usually needs one coat at the same coverage. This calculator is for topcoat only.
What if my paint covers 12 m² per litre?
Change the coverage box to 12 and the answer updates instantly.
Does this include the ceiling?
No. Ceilings are not included. Add the ceiling area separately if you plan to paint it.