Paint Coverage Calculator

Work out exactly how many litres of paint your room needs — walls, ceiling, doors and windows accounted for.

Room Details

Paint Required

Paint Needed
0 L
Paintable Area
0 sq ft
0 sq ft
Wall Area
0 sq ft
Doors/Windows Deducted
0 sq ft
Total Area (all coats)
₹0
Est. Cost
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How Paint Quantity is Calculated

Paint quantity comes down to paintable area, number of coats, and your paint's coverage rate.

Step 1: Wall area

Wall Area = 2 × (Length + Width) × Height

This is the total area of all four walls of a rectangular room. Tick "Include ceiling" to add the room's floor-plan area (Length × Width) as well, since a flat ceiling covers the same footprint as the floor.

Step 2: Deduct doors and windows

Multiply the number of doors and windows by their area each, and subtract from the wall area — these surfaces aren't painted with wall emulsion.

Step 3: Multiply by coats, divide by coverage

Litres = (Paintable Area × Coats) ÷ Coverage per Litre

Coverage rate is printed on the paint can and varies by product — this calculator defaults to 120 sq ft/litre, a reasonable mid-range figure for interior emulsion, but you should use your specific paint's stated rate for an accurate result.

SurfaceTypical area deducted
Standard interior door (~7ft x 3ft)21 sq ft
Standard window (~5ft x 3ft)15 sq ft

What this calculator doesn't include

For example, a 12ft × 10ft room with 10ft-high walls, 1 door and 2 windows, painted with 2 coats at 120 sq ft/litre coverage, needs a wall area of 440 sq ft, minus 51 sq ft of openings = 389 sq ft paintable, roughly 6.5 litres for 2 coats. Enter these same figures into the calculator above to reproduce this result.

Frequently Asked Questions

Calculate your wall area (2 × (Length + Width) × Height, minus door/window area), multiply by the number of coats, then divide by your paint's coverage rate (typically 100-140 sq ft per litre per coat for emulsion paint). For a typical 12x10ft room with 10ft walls and 2 coats, that's usually 3-4 litres.

Two coats is standard for most interior emulsion paints, giving even, opaque coverage over a primed wall. A single coat is sometimes used for a quick touch-up over an already-painted surface in a similar shade, while three coats may be needed for a major color change (e.g. dark to light) or an unprimed surface.

Yes, significantly — coverage can range from about 100 sq ft/litre for textured or exterior paints to 140-160 sq ft/litre for premium smooth interior emulsions. Always check the coverage figure printed on your specific paint can and adjust the default in this calculator to match it for an accurate estimate.

Yes — unpainted openings like doors and windows should be subtracted from your gross wall area, otherwise you'll overestimate the paint needed. This calculator does this automatically using a standard area per door and window, which you can adjust for non-standard sizes.

A standard Indian interior door (about 7ft x 3ft) accounts for roughly 21 sq ft, and a standard window (about 5ft x 3ft) for roughly 15 sq ft. Actual sizes vary, so measure yours directly for a more precise deduction on unusually large or small openings.

Yes — primer and finish paint are applied separately and often have different coverage rates. This calculator estimates finish/topcoat paint only; for primer, run the same paintable area through the calculator again using your primer's specific coverage rate (usually similar to, or slightly higher than, emulsion paint).

Tick the "Include Ceiling" option to add the room's floor-plan area (Length × Width) to the paintable area, since a flat ceiling covers the same footprint as the floor. Ceiling paint often has different coverage and finish (usually flat/matte) than wall emulsion, so check its coverage rate separately if buying a different product.

The litres this calculator shows is the theoretical minimum based on area and coverage rate. In practice, paint is sold in fixed can sizes (1L, 4L, 10L, 20L), so you'll usually round up to the nearest can size combination, and many painters add a small buffer (5-10%) for touch-ups later.