Paint Coverage Calculator
How much paint a room needs depends on wall area, number of coats, and the specific paint's coverage rate — skip any one of the three and you'll either run short mid-job or over-order.
Inputs
Result
10.91 litres
Buy 3 × 5 L tins
How the paint coverage calculator works
Litres needed = (wall area × number of coats) ÷ coverage per litre.
Tins to buy = round up litres needed divided by tin size (5 L used here as a common size).
Worked example: 60 m² wall area, 2 coats, 11 m² per litre coverage
- Litres = (60 × 2) ÷ 11 = 120 ÷ 11 ≈ 10.91 L.
- Tins: 10.91 ÷ 5 = 2.18, rounded up to 3 × 5 L tins.
Common mistakes to avoid
Using the coverage figure from the tin label without adjustment for surface texture
Rough, porous, or previously unpainted surfaces absorb more paint than the label's coverage rate assumes, which is usually measured on a smooth, primed reference surface.
Forgetting that a dark-to-light colour change may need extra coats
The number of coats entered should reflect the real job — going from a dark existing colour to a much lighter one often needs a third coat beyond the standard two, which this calculator will happily account for once told.
Frequently asked questions
Why does the calculator round up to whole tins?
Paint is sold in fixed tin sizes, so a requirement of 10.91 litres genuinely needs 3 tins of 5 L (15 L total) even though only about 11 litres will actually be used.
How do I account for doors, windows, and other areas not being painted?
Subtract their combined area from the total wall area before entering it, since paint isn't needed there.
Does ceiling area need to be calculated separately?
Yes — ceilings often use a different coverage rate and are usually a separate area calculation from wall area.
What if my paint's coverage rate isn't given on the tin?
Many standard interior paints fall in the 10-13 m² per litre range per coat, but check the specific product's data sheet where possible for accuracy.
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