Paint Calculator
Estimate how much paint a room needs — liters, coats and cans.
The Paint Calculator estimates how much paint a room needs before you buy a drop too much or too little. Enter the room's length, width and ceiling height, subtract your doors and windows, choose the number of coats, and read the wall area and liters required — plus how many 5 L or 10 L cans to bring home.
Paint math trips up DIYers twice: forgetting that two coats is standard (dark-to-light repaints often need three), and guessing coverage. Most wall paints cover 8–12 m² per liter per coat; the tool defaults to 10 and lets you match your can's label.
Buying a little extra is smart — touch-ups after furniture moves need the same batch. The estimate runs locally in your browser and works in any room shape you can reduce to a rectangle.
Usually 8–12 for wall paint.
Wall area to paint
41.5 m²
minus 3.5 m² for openings
Paint needed
8.3 liters
2 coat(s)
≈ 5 L cans
1.7
buy up to the next whole can
≈ 10 L cans
0.8
Doors subtract ~2 m², windows ~1.5 m² each. Real coverage varies with roller type and wall texture — textured walls can eat 20% more.
How to use the Paint Calculator
- Enter room length, width and ceiling height in meters.
- Set the number of doors and windows to subtract.
- Choose how many coats you will apply.
- Enter the paint's coverage (m² per liter, from the can).
- Read the liters needed and can sizes to buy.
Frequently asked questions
How much area does a liter of paint cover?
Typically 8–12 m² per liter per coat for interior wall paint. Check your can's label — the tool lets you enter the exact figure, and textured walls or poor-quality rollers can reduce real coverage by 20%.
How many coats will I need?
Two coats are standard for a uniform finish. Three are common when covering dark walls with light paint or using cheap thin paint; primer over fresh plaster counts as its own coat.
What about ceilings and trim?
This calculator covers walls only. For a ceiling, treat the room's floor area as a separate wall calculation; for trim, measure linear meters and expect roughly 8–10 m² of trim per liter of trim paint.
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