How Much Paint Do You Need?

This Page Was Last Updated: June 02, 2022
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You need 1.08 gallons of paint and 1.72 gallons of primer to cover this room’s surface area of 40 square meters.

The estimated time is 0.21 hours and the estimated cost is $100.00.

About This Paint Calculator

Looking to paint your home but don't know how much paint you'll need? Use this paint calculator to find out how much gallons of paint you will need, the coverage area, estimated time it will take to paint, and how much the paint would cost.

The "basic input" is for a rectangular-shaped room. It also assumes that the doors will not be painted. To calculate the paint required for other room types, the "advanced inputs" allows you to enter the specific width and height of the walls, along with calculating paint for a room with more than four walls. For example, if you are painting the walls, input the dimensions of each wall into the calculator. You can also choose the dimensions of any moulding and trims, whether doors will be painted or not, the paint and primer coverage, and the number of coats.

Estimating How Much Paint You Need

The paint estimate that this paint calculator provides is based on one gallon of paint covering 400 square feet and one gallon of primer covering 250 square feet. That’s about 37 square meters per gallon can of paint and 23 square meters per gallon can of primer. These area coverage values will differ depending on the brand and quality of paint you choose, as well as other factors like the type of surface you're painting and how many coats you need. Rough, uneven, and coarse walls will require more paint compared to a smooth wall. You will also need more coats of paint if you are going from a dark colour to a light colour.

To estimate how much paint you will need for a given space, start by measuring the square footage of the area that needs to be painted. Once you have that figure, divide the total area by the coverage of the paint and primer. For example, if the area being painted is 800 square feet and your paint covers 400 square feet per gallon, then you will need two gallons of paint. This will give you an estimated amount of paint required.

You may want to consider the type of paint you'll be using. Some paints cover better than others, so you may need less paint if you're using high-quality paint. A lower-quality paint might mean that you may need more paint to achieve the same coverage. This can even make a cheaper paint brand more expensive, as you will need to buy more paint for the same area.

Where to Buy Paint in Canada

Home improvement stores, such as Lowe's, Rona, The Home Depot, and Home Hardware all sell paint. There are even specialized paint stores in Canada, such as Benjamin Moore and Sherwin-Williams. Paint stores may offer additional advice and expertise that can be helpful, especially for novice painters or those working on a challenging project. However, these stores may charge higher prices than big box stores.

How to Calculate Paint Area

Paint area refers to the total square footage or square meters of a space that will be painted. A simple way to calculate paint area is to measure the height and width of each wall or surface that needs to be painted, then add those figures together to get the total square footage. A common mistake when calculating is multiplying the length and width of the room to get the room’s square footage. This is simply the room’s floor area, not the total area of the walls! For example, let’s say that you are painting a four-sided room. Two walls have a length of 6 meters, and two walls have a length of 3 meters. The room’s ceiling height is 3 meters. Your paint area would not be found by multiplying 6 meters by 3 meters. Instead, you will need to add up the area of each individual wall:

Wall 1 = 6 meters x 3 meters = 18 sq. m.

Wall 2 = 6 meters x 3 meters = 18 sq. m.

Wall 3 = 3 meters x 3 meters = 9 sq. m.

Wall 4 = 3 meters x 3 meters = 9 sq. m.

Total Wall Surface Area = 18 + 18 + 9 + 9

Total Wall Surface Area = 48 square meters

The surface to be painted in this room is 600 square feet. However, this calculation is missing some important information. A room might have windows, and in all cases, a room needs to have a doorway! When calculating paint area, you need to keep in mind that doors and windows must also be accounted for. Doors can either add to the paint area or take away from it. If there is no door to be painted, it will reduce the wall space that needs to be painted. If you are planning on painting the doors, you may also need to take into account the sides of the door.

Using the same example, let’s say that a doorway takes up 30 square feet of space. You don’t plan on painting the door. This means that you would subtract 30 square feet from the surface area of the wall in question. This gives a total wall surface area of 570 square feet from the prior example.

Moulding, Trims, and Baseboards

Another factor to keep in mind when calculating paint required is the presence of moulding, trims, and baseboards. While they will reduce the wall area to be painted, they themselves will also need to be painted. This paint calculator allows you to account for crown mouldings, wall trims, and baseboards.

Painted Ceilings

Painted ceilings can enhance the beauty of any room, making it appear more open and spacious in the case of lighter colours or make it more intimate and refined in the case of darker colours. The calculation for the paint required for a ceiling is the same as painting a wall. Multiplying the length by the width of the ceiling would give you the total paintable area.

The calculators and content on this page are provided for general information purposes only. WOWA does not guarantee the accuracy of information shown and is not responsible for any consequences of the use of the calculator.