Paint Calculator
Work out how much paint a room needs, with the doors and windows taken out of the sum.
Paint Calculator
Paint you need
8.48
- Area to paint509
- Paint will cost about₹3,393.33
- 20 litre buckets0.42
Works out in your browser. Nothing you type is sent anywhere.
In short: Paint Calculator
A room this size has 509 square feet to cover once the doors and windows are taken out, which needs 8.48 litres for the coats chosen, or 0.42 of the large buckets. At the price entered that comes to about ₹3,393.33.
What is Paint?
Paint quantity is the wall area to be covered, times the number of coats, divided by how much area a litre covers.
How is Paint calculated?
Work out the wall area from the perimeter times the height, take off the doors and windows, add the ceiling if you are painting it, multiply by the number of coats, and divide by the area a litre covers.
- Lthe litres of paint needed
- Athe area to be painted, in square feet
- cthe number of coats
- vthe area one litre covers, in square feet
A worked example
| Room length (ft) | 12 |
|---|---|
| Room width (ft) | 10 |
| Wall height (ft) | 10 |
| Doors | 1 |
| Windows | 2 |
| Coats of paint | 2 |
| Paint the ceiling too | Yes |
| Coverage a litre (sq ft) | 120 |
| Price a litre | ₹400 |
| Result | |
| Paint you need | 8.48 |
| Area to paint | 509 |
| Paint will cost about | ₹3,393.33 |
| 20 litre buckets | 0.42 |
Every figure in this table is produced by the same calculation the tool above runs.
How to use this paint calculator
- Enter the room's length, width and wall height.
- Enter how many doors and windows there are, so their area comes off.
- Set the number of coats, and whether the ceiling is being painted.
- Adjust the coverage to the figure on the tin you are buying.
Questions people ask
How much area does a litre of paint cover?
Around a hundred and twenty square feet in one coat on a smooth, previously painted wall, which is the figure this tool starts with. Fresh plaster, a rough finish or a dark colour going over a light one all soak up more. The tin states the maker's own figure, and that is the one to use.
How many coats will I need?
Two is standard over an existing similar colour. Covering a dark colour with a light one, or painting new plaster, often takes three. A primer coat is counted separately and is usually a different product.
Should I buy exactly the amount shown?
Buy a little more. Touching up later with a tin mixed at a different time can show, and running out part way through a wall leaves a visible join. Rounding up to the next bucket size is the usual advice.
Does this include the ceiling?
Only if you say so above, and then it adds the floor area as the ceiling area. Ceilings are often painted in a different, cheaper product, in which case work them out separately. The tool keeps the ceiling area visible so you can split the order.
Accuracy and sources
Where the figures come from
Checked by the Daytoolz team on 16 October 2026. How we check our tools.