Paint Calculator
Estimate how many litres of paint you need from wall area, number of coats, coverage and a waste allowance.
Set your values
Adjust the values, then calculate your result.
How to use Paint Calculator
- Enter the measurements or amounts in the fields above.
- Check that dimensions, rates and units match the labels.
- Select “Estimate paint” to see a clear estimate and the formula used.
How the paint calculator works
Paint litres = wall area × coats × (1 + allowance) ÷ stated coverage per litre. Round up to practical whole-litre cans.
Check your measurements and assumptions
Enter the total paintable wall area in square metres. Subtract large openings yourself and check the coverage printed on the paint can; textured surfaces can use more paint.
Review the estimate before you act
Compare this result with an independent measurement, supplier quote or institution guidance when the decision matters. Confirm that the units and assumptions match the labels above, and update the inputs when the conditions change. Keep a note of the values used so you can reproduce the estimate later. This calculator is a planning aid and does not replace professional, product-specific or local guidance.
How much paint do I need for two coats?
Add the wall areas, multiply by two, then divide by the coverage per litre. This estimate adds your selected allowance and rounds up.
Is input uploaded?
Processing takes place in your browser. This tool does not send your input or selected files to a conversion API.