Enter your room size and number of coats to get the exact paint quantity in liters, plus estimated cans and cost.
Paint is usually bought by the can, not the exact liter, which means a rough guess either leaves an odd amount of unusable leftover paint or forces a last-minute second trip to the store mid-job — awkward when a wall is half-painted and the shade needs to match exactly. Getting the area and coat count right upfront avoids both problems.
The two details people most often skip are the second coat (which roughly doubles the required paint versus a single coat) and door/window deductions (which can overstate the area by 15-20% in a room with several openings). This calculator accounts for both automatically.
A few common situations
Estimate paint quantity for an entire bedroom, living room, or office before buying.
Calculate the smaller quantity needed for a single feature wall in a contrasting color.
Plan paint purchases for multiple rooms in a new build, room by room.
Cross-check a painter's material estimate against an independent calculation before approving a quote.
Approximate — always check the specific product's label
| Paint type | Surface | Coverage (sq ft / liter) |
|---|---|---|
| Interior emulsion | Smooth, previously painted wall | 130-140 |
| Interior emulsion (first coat) | Bare plaster / new wall | 100-110 |
| Exterior emulsion | Textured exterior surface | 90-110 |
| Primer / wall putty finish | Bare plaster | 110-120 |
| Ceiling paint (flat white) | Smooth ceiling | 130-150 |
2 coats, 1 door, 2 windows, 130 sq ft/liter coverage
Wall perimeter = 2 × (12 + 10) = 44 ft
Gross wall area = 44 × 9 = 396 sq ft
Deductions = (1 door × 21) + (2 windows × 15) = 21 + 30 = 51 sq ft
Paintable area = 396 − 51 = 345 sq ft
Paint per coat = 345 ÷ 130 ≈ 2.65 liters
Total for 2 coats = 2.65 × 2 ≈ 5.3 liters
Cans needed (4L cans) = 2 cans (rounded up from 1.33)
Two coats is the standard recommendation for nearly all interior repainting, and skipping straight to one coat to save paint often backfires — a single coat over most colors shows roller marks, patchy opacity, and inconsistent sheen once it dries, meaning the job needs to be redone anyway.
A third coat becomes worth considering in two specific situations: going from a dark existing color to a much lighter new one (where two coats may still show the old color faintly through), or for high-traffic areas like a hallway or a rental property where extra durability against scuffs matters more than usual.
Primer is a separate consideration from coats — it's not a substitute for the topcoat but a preparation layer, typically needed once for bare plaster or a major color change, and not counted in the "number of coats" figure used for coverage calculations here.
Two coats is the standard recommendation for most interior walls, giving even, opaque coverage. A third coat is rarely needed except for very light colors going over a dark base or for extra durability in high-traffic areas.
Most interior emulsion paints cover roughly 120-140 square feet per liter per coat on a smooth, previously painted wall. Rough surfaces and bare plaster typically need more paint.
Yes. A standard door is roughly 21 sq ft and a standard window is roughly 15 sq ft, though exact sizes vary — subtracting them avoids over-ordering.
A primer coat is recommended for bare plaster, new walls, or when changing from a dark color to a much lighter one. For a simple repaint in a similar shade, primer is often skipped.
Yes, ceilings are usually painted with a separate ceiling paint and should be calculated as their own area rather than combined with wall area.
A small amount is inevitably left in trays, rollers, and brushes. Buying a slightly rounded-up quantity naturally accounts for this.
Common sizes in India are 1 liter, 4 liters, 10 liters, and 20 liters. Larger cans are more cost-effective per liter for bigger jobs.
Yes. Textured surfaces have more surface area per square foot of wall and generally require 10-20% more paint than a smooth surface.
Enter the price per can alongside the required quantity, and it will estimate the total cost based on the number of cans needed, rounded up to whole cans.
The area calculation method is the same, but exterior paints often have a different coverage rate — check the specific product's coverage rate rather than assuming the interior figure.