Paint Calculator

Estimate the exact amount of paint needed for any wall surface in litres or gallons.


What Is the Paint Calculator?

Estimating paint requirements for a home renovation or new construction project can be challenging. Our Paint Calculator helps you determine exactly how much paint you need based on room dimensions, number of coats, and paint coverage rates, saving you money and reducing waste.

Paint coverage depends on the surface material, paint type, and application method. Typically, 1 litre of paint covers about 100-140 square feet for one coat. By measuring your walls, ceiling, and trim separately, this calculator provides an accurate estimate for each component.

Homeowners planning renovations, contractors preparing project quotes, and DIY enthusiasts tackling painting projects will benefit from this calculator.

How to Use This Calculator

1

Enter room dimensions

Input length, width, and height of the room in feet or metres.

2

Select the number of doors and windows

Doors and windows reduce the paintable area. Enter the count or dimensions.

3

Choose the number of coats

Most walls need 2 coats for even coverage. Darker colours or drastic colour changes may need 3.

4

Select paint type and coverage rate

Different paints have different coverage rates. Emulsion, enamel, and primer each cover differently.

5

Review the estimate

See total paint required in litres for walls, ceiling, and trim with cost estimate.

Real-World Example

Meet the Patel family. The Patels are renovating their 12ft x 14ft bedroom in their Ahmedabad home. The room has a 10ft ceiling, one door, and two windows. They want to paint the walls and ceiling with two coats of emulsion paint and need to estimate how many litres to buy and the total project cost.

Using the Paint Calculator:

Room Size

12ft x 14ft x 10ft

Doors / Windows

1 door / 2 windows

Coats Required

2

Wall Paint Required

5.6 litres

Ceiling Paint Required

2.1 litres

Total Estimated Cost

~4,500

The Patels buy 6 litres of wall paint and 2.5 litres of ceiling paint (including 10% buffer for waste). They complete the painting over a weekend and have enough leftover paint for future touch-ups, avoiding the common problem of colour mismatch from separate batches.

Paint Requirement Formula

Total paint needed is calculated by dividing the paintable area by the coverage rate per litre and multiplying by the number of coats.

Paint Required = (Total Area - Door/Window Area) × Number of Coats / Coverage Rate per Litre
Total Area= Sum of all wall and ceiling surface areas
Door/Window Area= Area subtracted for doors and windows that will not be painted
Number of Coats= How many layers of paint will be applied (typically 2)
Coverage Rate= Area covered by one litre of paint (typically 100-140 sq ft)

Frequently Asked Questions

Typically 100-140 sq ft per litre for one coat. Smooth surfaces covered with good quality paint give higher coverage. Rough or porous surfaces reduce coverage.

Buy 10% extra for touch-ups and waste. Leftover paint sealed properly can last 2-3 years for future touch-ups.

Primer usually covers less area than paint, typically 80-100 sq ft per litre. Follow manufacturer guidelines for best results.

Textured walls require 15-20% more paint than smooth walls because the textured surface has greater effective area. Use a lower coverage rate of 80-100 sq ft per litre for textured or rough plaster surfaces.

Ceilings typically use a different paint formulation than walls. Ceiling paint is thicker to prevent drips and has higher opacity for better coverage. Wall paint is formulated for easier cleaning and stain resistance.

A standard Indian 3BHK apartment (approximately 1,200-1,500 sq ft carpet area) requires about 15-20 litres of wall paint and 5-8 litres of ceiling paint for two coats. For a 2BHK (800-1,000 sq ft), you need about 10-14 litres for walls and 4-5 litres for the ceiling.

For Indian weather, use anti-fungal and moisture-resistant paints, especially in coastal cities like Mumbai, Chennai, and Kochi. Brands like Asian Paints Royale Shyne, Berger WeatherCoat, and Dulux Weathershield offer specialized formulations. For bathrooms and kitchens, use satin or semi-gloss enamel.

Yes, primer is essential, especially for new plaster walls common in Indian construction. Primer ensures better paint adhesion and uniform absorption. One litre of primer typically covers 80-100 sq ft. Using primer can reduce the number of paint coats needed from 3 to 2.

Calculate total litres needed, multiply by cost per litre (INR 200-600 for economy, INR 600-1,500 for premium emulsion). Add primer cost, painter charges (INR 8-15 per sq ft), and materials. For a standard 3BHK, total painting cost ranges from INR 40,000 to 1,00,000 depending on paint quality.

Textured walls require 15-20% more paint than smooth walls because the surface has greater effective area. Use a lower coverage rate of 80-100 sq ft per litre for textured or rough plaster surfaces. Consider using textured paint that combines texture and color in one application.

Key Takeaways

1

Accurate room measurements are essential for paint estimation.

2

Subtract doors and windows from paintable area.

3

Most rooms need 2 coats for even coverage.

4

Different surfaces affect paint coverage rates.

5

Buy 10% extra for waste and future touch-ups.

Why This Matters

Buying too much paint wastes money. Buying too little means colour matching issues. An accurate calculator saves both money and the frustration of mismatched batches.

This calculator is for educational and planning purposes. Consult a qualified professional for personalized advice.