Estimate how much paint a room needs

The job

Paint coverage is on the can in m² per litre per coat — the missing piece is how many square metres your walls actually are, minus the doors and windows you won't paint.

Measure and enter

Enter length, width, and ceiling height; set the door and window count; choose whether the ceiling gets painted. The tool subtracts standard openings (door 1.9 m², window 1.5 m²) and applies your coats and coverage rate.

• Two coats is the realistic default for colour changes.
• Coverage varies: smooth plaster might do 12 m²/L, rough texture closer to 8 — check the can.

Worked example

A 4 m × 3 m room at 2.4 m height with one door and one window: about 31 m² of wall. Two coats at 10 m²/L needs ~6.2 L — so one 5 L can plus a 2 L top-up, or two 4 L cans.

Before you buy

The estimate covers walls and an optional ceiling at standard opening sizes — closets full of shelving, wainscoting, or dark-over-light colour changes can push real usage up. Round up on the small side: a sealed leftover can keeps for touch-ups.

• Optional can-size and price fields turn litres into a cost estimate.
• All arithmetic is local; nothing is sent anywhere.