How much paint for a 3×4 m room (12 m²)
A 3×4 m room has 34.5 m² of walls excluding the door and window and 12 m² of ceiling. Below is how much paint each surface takes in two coats.
Walls
4tins
To buy
Needed: 9.5 l
2.5 l each = 10 l
Estimated leftover: 0.5 l
Thinner: Water (5–10 %). About 0.76 l for the whole volume.
What to buy
Water-based (acrylic) paint, 2.5 l can · 2.5 l each = 10 l4 pcs
Thinner: Water · 5–10 %0.76 l
Where this number comes from
34.5 m² × 2 coats ÷ 8 m²/l = 8.6 l, + 10% reserve = 9.5 l → 4 tins of 2.5 l (10 l).
Ceiling
2tins
To buy
Needed: 3.3 l
2.5 l each = 5 l
Estimated leftover: 1.7 l
Thinner: Water (5–10 %). About 0.26 l for the whole volume.
What to buy
Water-based (acrylic) paint, 2.5 l can · 2.5 l each = 5 l2 pcs
Thinner: Water · 5–10 %0.26 l
Where this number comes from
12 m² × 2 coats ÷ 8 m²/l = 3 l, + 10% reserve = 3.3 l → 2 tins of 2.5 l (5 l).
Paint: interior water-based
For walls and ceilings. In kitchens and bathrooms pick a washable one, scrub class 1–2 (EN 13300).
Tip from the trade
Apply the second coat perpendicular to the first and use paint from one batch — no streaks or colour differences.
How we calculated
Ceiling height 2.7 m, one door and one window. Water-based acrylic paint, coverage 8 m²/l, smooth substrate, 2 coats, 10% reserve, 2.5 l can.
If yours differs — open the calculator and change the dimensions, it will recalculate.