Paint Calculator
Calculate paint quantity from room dimensions and coats.
Check the tin — coverage varies by paint type
Paint needed
6.5 L
About 6.5 L before rounding up
Net wall area
39 m²
Area × coats
78 m²
Gross walls
43.2 m²
In-depth explanation
Estimate paint from room size, wall height, coats, and coverage on the tin. Doors and windows are deducted with simple averages. Everything runs locally in your browser — your inputs are not uploaded to produce the result.
Perimeter walls (2 × (length + width) × height), minus approximate door and window areas. Use the figure on your paint tin. Many emulsion paints cover about 10–14 m² per litre (or ~300–400 ft² per gallon).
Rounding up slightly helps with touch-ups and darker colours that need more coats. Tweak the inputs above to compare options, then copy or note the result you need.
Perimeter × height is a box-room model. Bay windows, stair voids, and coving change the area. Coverage on the tin assumes a prepared surface; new plaster often needs a mist coat and more volume.
Buy an extra tin of the same batch for touch-ups. Dark colours and feature walls may need more coats than the default. The longer paint guide walks through the arithmetic if you want to check by hand.
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Frequently asked questions
How is wall area calculated?
Perimeter walls (2 × (length + width) × height), minus approximate door and window areas.
What coverage should I use?
Use the figure on your paint tin. Many emulsion paints cover about 10–14 m² per litre (or ~300–400 ft² per gallon).
Should I buy extra?
Rounding up slightly helps with touch-ups and darker colours that need more coats.
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