DIY Interiors

Calculating Paint Requirements

How much paint do I need?

Use the easy steps below to determine the right amount of paint to purchase.

Step One: The Perimeter

Measure the perimeter of your room (length and width, in metres). Add all 4 numbers together.

Length  +  Length  +  Width  +  Width  =  Total Perimeter (m)

Step Two: The Height

Multiply the perimeter by the height.

Total Perimeter  x  Height  =  Gross Area (m²)

Step Three: Doors & Windows

Deduct windows and doors. An average window is approximately 1.5 m² and an average door is 2.5m².

Gross Area(m²)  -  Doors & Windows (m²)  =  Total Area (m²)

Step Four: Paint Loss Compensation

To compensate for minimal paint loss, divide Total area by 14

Total Area(m²)  /  14  =  Number of Litres required per coat

The table below is a guide to the number of litres required per coat. Actual usage will vary depending on application technique, surface texture and porosity.

Wall Dimensions - distance in metres around the room
Wall height (m) 10m 12m 14m 16m 18m 20m 22m
4.0m 2.5L 3.0L 3.5L 4.0L 4.5L 5.0L 5.5L
3.7m 2.5L 3.0L 3.5L 3.5L 4.0L 4.5L 5.0L
3.4m 2.0L 2.5L 3.0L 3.5L 4.0L 4.5L 4.5L
3.1m 2.0L 2.5L 3.0L 3.0L 3.5L 4.0L 4.5L
2.8m 2.0L 2.0L 2.5L 3.0L 3.0L 3.5L 4.0L
2.5m 1.5L 2.0L 2.5L 3.0L 3.0L 3.5L 3.5L
2.2m 1.5L 2.0L 2.0L 2.5L 2.5L 3.0L 3.5L

Decide on Water based or Oil based Paint

Today's water based paints perform just as well as oil based products!

Water based paints are better for our environment, more convenient as they are low in odour, faster drying, easy to use and wash up in water. Some, such as Pascol TRIM Water Based, have better exterior durability than oil based enamels.

Keep reading...

Step 1: How much paint do I need?

Step 2: Which sheen should I use?

Step 3: Choosing the right Prep Coat

Step 4: Prepare the surface

Step 5: Let's paint Ceilings and Walls

Step 6: Let's paint Trims and Woodwork

Step 7: Which tools do I need?

Step 8: Clean-up, storage & disposal

Guide Download

Download a PDF of our DIY Exterior Painting Guide

See also