Paint Calculator

How much paint do I need for a 12x12 room?

A 12x12 foot room (about 3.65 x 3.65m) with 2.5m ceilings has roughly 36.5 m2 of wall area. After subtracting a standard door (0.8 x 2.1m = 1.7 m2) and a standard window (1.2 x 1.2m = 1.4 m2), the paintable area is about 33.4 m2. At 2 coats and 10 m2/liter coverage, you need approximately 6.7 liters. A 10-liter can gives you plenty with room for touch-ups.

How many square meters does 1 liter of paint cover?

On average, 1 liter of interior wall paint covers 10-12 square meters per coat on a smooth surface. Coverage varies by paint type: premium paints may cover up to 14 m2/L, while textured or porous walls may reduce coverage to 6-8 m2/L. Always check the coverage rate printed on your paint can.

Do I need 2 coats of paint?

Yes, 2 coats is the industry standard for a professional-looking finish. A single coat often shows brush marks, uneven color, and poor coverage - especially when painting over a darker color. Some high-quality one-coat paints exist, but even professionals recommend 2 coats for durability and even coverage.

How do I calculate paint for walls only, not the ceiling?

Measure the wall area using the formula: 2 x (length + width) x height. Then subtract the area of each door and window using their exact width and height. Multiply by the number of coats and divide by coverage per liter (typically 10 m2/L). Our calculator does this automatically with custom door and window dimensions - just leave the Include ceiling option off.

How much extra paint should I buy for touch-ups?

Buy 10-15% more paint than calculated. This covers touch-ups after moving furniture, minor scuffs, and any spots that need extra attention. For a typical room needing 8 liters, rounding up to a 10-liter can is ideal. Leftover paint stored properly lasts 2-5 years for future repairs.

Does wall texture affect how much paint I need?

Yes, significantly. Smooth drywall uses the standard 10-12 m2/liter. Textured surfaces like stucco, brick, or rough plaster can use 30-50% more paint because the texture creates extra surface area. For heavily textured walls, use 6-8 m2/liter as your coverage rate - you can adjust this in our calculator.

What size paint can should I buy?

Paint typically comes in 1L, 2.5L, 5L, and 10L cans. For a single room, a 5L or 10L can is usually best value. For touch-ups only, a 1L can suffices. Our calculator recommends the most efficient combination of can sizes to minimize waste and cost. Buying one larger can is almost always cheaper per liter than multiple smaller cans.

How much does it cost to paint a room?

DIY painting costs are primarily the paint itself: 15-40 EUR per liter for quality interior paint. A typical bedroom (3x4m) needs about 7 liters for 2 coats, costing 100-280 EUR in paint alone. Add 20-50 EUR for supplies (rollers, tape, drop cloths). Professional painters charge 200-600 EUR per room depending on size and complexity.