How much paint for a 3×5 m room (15 m²)
A 3×5 m room has 39.9 m² of walls excluding the door and window and 15 m² of ceiling. Below is how much paint each surface takes in two coats.
Walls
5tins
To buy
Needed: 11 l
2.5 l each = 12.5 l
Estimated leftover: 1.5 l
Thinner: Water (5–10 %). About 0.88 l for the whole volume.
What to buy
Water-based (acrylic) paint, 2.5 l can · 2.5 l each = 12.5 l5 pcs
Thinner: Water · 5–10 %0.88 l
Where this number comes from
39.9 m² × 2 coats ÷ 8 m²/l = 10 l, + 10% reserve = 11 l → 5 tins of 2.5 l (12.5 l).
Ceiling
2tins
To buy
Needed: 4.1 l
2.5 l each = 5 l
Estimated leftover: 0.9 l
Thinner: Water (5–10 %). About 0.33 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 %0.33 l
Where this number comes from
15 m² × 2 coats ÷ 8 m²/l = 3.8 l, + 10% reserve = 4.1 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.