Paint Calculator

Estimate how many litres or gallons of paint a room needs from its size, openings and number of coats. Enter the room length, width and height, the number of doors and windows, and how many coats you plan to apply. This is an approximate estimate for planning and shopping, not a quote; check the manufacturer's coverage figure and your local requirements. All processing runs locally in your browser. Your data is not uploaded to any server. 100% Local

How to Use the Paint Calculator

Choose your units, then enter the room length, width and wall height, the number of doors and windows, and the number of coats. Press Calculate paint to see the paintable wall area and the paint volume in litres and US gallons.

What it accounts for

• Walls only: 2 x (length + width) x height.
• Openings are subtracted using approximate areas per door (1.8 m2) and per window (1.5 m2).
• Coverage is estimated at about 10 m2 per litre, per coat.

Getting a better number

Coverage varies a lot with the paint and the surface. A rough or porous wall, a strong colour change or a primer coat will need more. Round up, and keep a little spare for touch-ups.

Features

• Paint volume in litres and US gallons
• Suggested 5 L cans or 1 gallon cans to buy
• Metric and imperial units
• All processing runs locally in your browser. Your data is not uploaded to any server.
• Results are approximate estimates, not a quote; check the manufacturer's coverage figures and your local building requirements.

For the most accurate figure, look at the coverage stated on the paint tin and divide your wall area by it, then multiply by the number of coats.

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