For a rectangular room using one coverage rate. Estimate different paints or different surfaces separately when their coverage differs.
- Room dimensions
- Length, width and height determine four-wall area. Ceiling and floor can each be included independently.
- Openings
- Width, height and count of surfaces to deduct once.
- Coverage and coats
- Area covered by one litre for one coat, or by one gallon in imperial mode; number of coats.
Walls are included in the room calculation. Add ceiling and/or floor with their switches, then add opening groups and choose the coat count.
- Wall area, added floor/ceiling area, opening area, net paintable area and area across all coats.
- Paint volume in litres, or gallons in imperial mode, from the chosen coverage rate.
Walls only: ceiling and floor off, one door, two coats.
| Quantity | Value |
|---|---|
| Room length × width × height | 5 × 4 × 2.8 m |
| Door width × height; count | 0.9 × 2.1 m; 1 |
| Coats; coverage | 2; 10 m²/L |
| Walls; opening; net area | 50.40; 1.89; 48.51 m² |
| All coats; paint | 97.02 m²; 9.702 L |
Wall area = 2 × (length + width) × height. Subtract the door, multiply net area by the coat count, then divide by coverage. Paint quantity is not a number of tins.
Coverage is product- and surface-dependent. The example does not add an automatic waste allowance or round to available tin sizes. Choose packaging separately.
Dimensions can use metric or imperial units. Keep the coverage unit consistent with the paint volume. Openings are summed without positions, so do not enter overlapping deductions twice.
Should I enter litres per square metre?
No. This field asks how many square metres one litre covers. If a data sheet gives consumption instead, convert it to coverage first.
Do two coats double the wall area?
The measured area stays the same; the total area to cover across coats doubles, which doubles the calculated paint quantity.
- Should I enter litres per square metre?
- No. This field asks how many square metres one litre covers. If a data sheet gives consumption instead, convert it to coverage first.
- Do two coats double the wall area?
- The measured area stays the same; the total area to cover across coats doubles, which doubles the calculated paint quantity.
Measurements, units and material terms
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