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Paint Area Calculator

Paint coverage needed. Fast, accurate, and completely free.

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Number of Walls

Wall 1

Wall 2

Wall 3

Wall 4

Number of Doors (2.1m × 0.9m each)

Number of Windows (1.2m × 1.2m each)

Number of Coats

Paint Coverage (sqm per liter)

Results

Paint Required

7.6 Liters

For 2 coat(s)

Area Breakdown

Total Wall Area

54.00 m²

Door Deductions

1.89 m²

Window Deductions

2.88 m²

Paintable Area

49.23 m²

Recommended Cans

20 L Cans

10 L Cans

4 L Cans

1 L Cans

Mathematical Formula

Paint = \frac{(A_{walls} - A_{openings}) \times Coats}{Coverage}

A_walls = Sum of all wall areas (Length × Height for each wall)

A_openings = (Doors × 2.1 × 0.9) + (Windows × 1.2 × 1.2)

Coats = Number of paint coats (1, 2, or 3)

Coverage = Paint coverage in sqm per liter (typically 10-14 sqm/L)

How to Use this Calculator

Select the Number of Walls you want to paint (1 to 6).
Enter the Length and Height (in meters) for each wall.
Enter the number of Doors (standard 2.1 m × 0.9 m) and Windows (standard 1.2 m × 1.2 m) to deduct.
Choose the number of coats (2 is recommended for most interior walls).
Set the paint coverage rate (12 sqm/liter is typical for emulsion paints).
Review the paintable area, total paint needed, and recommended can sizes.

What is a Paint Area Calculator?

A paint area calculator is a handy tool that helps homeowners, painters, and interior designers estimate the exact amount of paint required to cover walls in a room or building. It calculates the total wall area, subtracts openings like doors and windows, accounts for the number of coats, and recommends the optimal combination of paint cans to purchase.

How Paint Coverage Works

Every can of paint comes with a coverage specification — the area it can cover per liter in a single coat on a smooth, primed surface. Typical values for popular Indian paint brands are:

Emulsion (interior): 10-14 sqm per liter (e.g., Asian Paints Royale, Berger Silk).
Distemper: 8-10 sqm per liter — economical but less durable.
Exterior paint: 8-12 sqm per liter (e.g., Apex Ultima, Weathercoat).
Primer/Sealer: 12-15 sqm per liter — applied as a base coat.
Textured paint: 3-5 sqm per liter due to thick application.

Why Multiple Coats Matter

A single coat of paint often leaves streaks, shows brush marks, and does not provide uniform color coverage, especially when changing from a dark to a lighter shade. Two coats are the industry standard for a professional finish. A third coat may be needed when:

Painting over dark or strong colors with a lighter shade.
Working with vibrant reds, oranges, or yellows that inherently require more coats.
Painting on new plaster that is highly absorbent.

Standard Opening Sizes in India

When deducting openings from the total wall area, the following standard sizes (as per IS 1081 and common architectural practice) are used:

Doors: 2.1 m height × 0.9 m width (standard internal door) = 1.89 m² each.
Windows: 1.2 m height × 1.2 m width (standard window) = 1.44 m² each.

Tips for Paint Estimation

Add 10% extra for touch-ups, uneven surfaces, and wastage.
Use a primer coat before painting on fresh plastered walls to reduce absorption.
Buy all cans from the same batch to ensure color consistency.
Dark colors typically require an additional coat compared to light or pastel shades.

Choosing the Right Can Size

Paint is available in 1 L, 4 L, 10 L, and 20 L cans. Larger cans are more economical per liter. Our calculator suggests the optimal combination of cans to minimize waste and cost.

Frequently Asked Questions (FAQ)

How much area does 1 liter of paint cover?

Most interior emulsion paints cover approximately 10-14 sqm per liter per coat on a smooth, primed surface. The actual coverage depends on the paint type, surface texture, porosity, and application method (brush, roller, or spray).

Should I include ceiling area in the calculation?

This calculator is designed for walls only. To paint the ceiling, calculate the ceiling area separately (Room Length × Room Width) and add it to the total. Ceiling paint may have different coverage rates.

Why is primer important before painting?

Primer seals the surface, provides a uniform base, improves paint adhesion, and reduces the number of topcoats needed. On new plaster, primer can reduce paint consumption by 20-30% because it prevents the porous surface from absorbing the topcoat.

How do I calculate paint for textured or rough walls?

Rough or textured surfaces like exposed brick, stucco, or textured plaster can use 15-25% more paint than smooth surfaces. Reduce the coverage value (e.g., from 12 to 9 sqm/liter) in the calculator to account for this.

Can I mix leftover paints of the same color?

Yes, you can mix leftover paints of the same brand, type, and color code. However, paints from different batches may have slight color variations. Mix all cans together in a large bucket ("boxing") before application for a uniform finish.

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