Work Out How Much Paint a Room Needs
A free paint calculator that estimates how much paint a room needs. Enter the room dimensions, the number of coats and the coverage printed on the tin, subtract the doors and windows, and it returns the paintable wall area and the litres or gallons to buy.
How to estimate paint
1
Enter the room size
Type the floor length, width and the wall height.
2
Subtract openings
Enter how many doors and windows are not being painted, and tick the ceiling if you are painting it.
3
Set coats and coverage
Choose the number of coats and copy the coverage figure from the paint tin.
Estimate the litres of paint before you decorate
Enter the floor length and width — wall area is worked out from the perimeter and height.
m
m
mheight
From the tin — typically 10–12 m²/L or about 350 ft²/gal.
m²/L
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Paintable area
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Paint per coat
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Total paint
Each door is counted as 1.8 m² and each window as 1.5 m² of unpainted area. Bare or dark walls may need an extra coat or a primer.
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