How much paint do I need for a room?

Multiply the room perimeter (2 × length + 2 × width) by the ceiling height to get wall area, subtract door and window areas, then divide by the paint's coverage rate (typically 10-12 m² per liter). Multiply by the number of coats and add 10% for waste.

How many coats of paint do I need?

Most rooms require 2 coats for even, opaque coverage. One coat may suffice if repainting with a similar color. Three coats are recommended when painting a light color over dark, covering stains, or painting new drywall. Always allow proper drying time between coats.

What is paint coverage rate?

Coverage rate (or spreading rate) is how many square meters one liter of paint covers in a single coat. It typically ranges from 10-12 m²/L for standard emulsion paints and 8-10 m²/L for thicker paints. Always check the specification on your paint tin.

Should I buy extra paint?

Yes — always buy 10-15% more than calculated. You will need extra for touch-ups, miscalculations, or future repairs. Paint colors can vary slightly between batches, so it is better to have excess from the same batch than to buy more later.

Do I need to include the ceiling?

This calculator covers walls only. For ceiling paint, calculate the floor area (length × width) and apply the same formula. Ceilings often need a different type of paint (matt finish) and typically require 2 coats on new surfaces.

Everyday

Paint Coverage Calculator

Calculate how much paint you need for a room. Enter wall dimensions and number of coats to get gallons and liters needed.

✏️

Enter Values

Room Length(m)*

Interior length of room

Room Width(m)*

Ceiling Height(m)*

Number of Doors

Each standard door ≈ 1.8 m²

Number of Windows

Each standard window ≈ 1.4 m²

Number of Coats

Paint Coverage Rate(m²/L)

Check your paint tin (typically 10-12 m² per liter)

📊

Results

Enter values above to see results

Paintable Area = Wall Area − Doors − Windows | Paint = Area × Coats ÷ Coverage

Variables

Wall AreaPerimeter × Height (sum of all 4 walls)

Coveragem² covered per liter (from paint tin)

CoatsNumber of paint layers applied

Explanation

Wall area is calculated as the perimeter (2 × length + 2 × width) × ceiling height. Door and window areas are subtracted as they are not painted. The result is divided by the paint's coverage rate and multiplied by the number of coats needed.

What is the Paint Coverage Calculator?

Calculating the right amount of paint before starting a painting project prevents both waste and frustrating mid-project trips to the hardware store. Whether you are refreshing a bedroom, redecorating a living room, or painting an entire house, accurate paint calculation saves money and time.

How to Use This Calculator

Enter your room dimensions, ceiling height, number of doors and windows, desired number of coats, and your paint's coverage rate. The calculator computes the paintable wall area and gives you the exact paint volume needed in both liters and gallons, plus a recommended amount with a 10% waste buffer.

Worked Examples

A 5 m × 4 m bedroom, 2 coats

Ceiling height 2.7 m, one door and two windows, paint that covers 10 m² per litre.

Wall area = 2 × (5 + 4) × 2.7: 48.6 m²
Less 1 door (1.8) + 2 windows (2.8): 44.0 m² paintable
Paint = 44 × 2 coats ÷ 10: 8.8 L
With a 10% waste buffer: 9.68 L (≈ 2.32 US gallons)

Buy about 10 litres (roughly a 2.5-gallon / 10 L pail).

Two coats doubles the paint — the single biggest factor people forget.

Why Use MyCalculatorsHub's Paint Coverage Calculator?

This calculator accounts for the areas you won't paint (doors and windows) and supports multiple coats, giving you a much more accurate estimate than simply calculating total wall area. The 10% waste buffer recommendation helps prevent running out of paint mid-project.

Common Mistakes to Avoid

Don't forget to account for the number of coats — painting with 2 coats requires double the paint compared to 1 coat. Also, different paint finishes (matte, eggshell, gloss) may have different coverage rates, so always check the specific paint you are buying.