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Paint Calculator

Calculate paint litres needed for any room.

Net paintable area
67.2 m²
Total area (all coats)
134.3 m²
Paint required
13.4 litres
Estimated cost
₹3358
Wall area: 54.0 m² · Ceiling: 20.0 m² · Deductions (doors + windows): 6.8 m²
Suggested cans: 3 × 4L + 2 × 1L (or adjust to available sizes)

How the Paint Calculator works

The paint calculator helps homeowners, contractors, and interior designers estimate exactly how many litres of paint are needed for any room. Enter your wall dimensions, number of doors and windows, paint type, coverage rate, and number of coats — the tool deducts non-paintable areas and adds a configurable waste factor so you buy the right amount first time.

Coverage rate and paint types

Different paints cover different areas per litre. Standard emulsion covers roughly 10–12 m² per litre per coat; exterior masonry paint around 10 m²; enamel or gloss 12 m²; and texture paint as little as 5 m² for the first coat. Selecting the correct paint type in the calculator applies the right coverage rate automatically.

Door and window deductions

Every door and window reduces the paintable wall area. A standard internal door (1.8 m × 0.9 m) accounts for 1.62 m², and a typical window (1.2 m × 1.0 m) deducts 1.2 m². Entering the count lets the calculator subtract these accurately, preventing over-ordering on rooms with many openings.

Coats, primer, and waste factor

New plasterwork typically requires one primer coat plus two finish coats. Repaints on already-coated surfaces often need just two finish coats. A waste factor of 5–10% accounts for brush drips, roller spatter, and touch-ups. The calculator multiplies total area by coats, adds waste, then divides by coverage rate to give the final litre requirement.

Cost estimation

Enter the price per litre of your chosen paint brand to see total material cost instantly. This lets you compare budget emulsions against premium brands before visiting the store, or quickly quote material costs to clients without leaving the browser.

Frequently asked questions

How much paint does 1 litre cover?
Coverage varies by paint type and surface texture. As a general guide: interior emulsion covers approximately 10–12 m² per litre on a smooth surface, exterior masonry paint covers approximately 10 m² per litre, enamel or gloss paint covers approximately 12–14 m² per litre, and texture paint covers approximately 4–6 m² per litre for the first coat. Rough or porous surfaces absorb more paint and reduce coverage by 20–30%.
How many coats do I need for interior walls?
For new construction on bare plaster walls, the standard specification is 1 coat of primer followed by 2 coats of interior emulsion. For repainting existing surfaces in good condition, 2 coats of finish paint without primer is typically sufficient. If the existing colour is dark and you are painting a lighter shade, an additional coat or a tinted primer may be required for full coverage.
How do I account for doors and windows?
A standard interior door (1.8 m × 0.9 m) has an area of 1.62 m² to deduct from the wall area. A standard window (1.2 m × 1.0 m) has an area of 1.2 m² to deduct. Enter the number of doors and windows and the calculator automatically subtracts the appropriate area from the total paintable wall surface before computing paint quantity.

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