Paint Calculator

How to Calculate Paint and Primer l

When you’re painting a room, a fence, or your whole house, you might be wondering how many gallons of paint you’ll actually need. There are a few methods to figure this out.

The first method is to use the paint calculator above. It estimates the amount of paint, primer, and ceiling paint you’ll need for any project.

Simply enter the size of the area, and the calculator finds the square footage of the walls, then estimates the paint and primer needed for that area.

Of course, you can estimate paint without a calculator as well. You can calculate how many gallons you need in a few simple steps.

How Many Gallons of Paint Do You Need?

The first step is to calculate the size of the area you will be painting. Paint is a most costly material, and while you do want a small amount extra for touch-ups later, you don’t want to order much more than you need, as it is not returnable.

By far, the easiest way to estimate how many gallons of paint you need for a project is to consult the quick reference table below.

Paint Coverage Estimates

This table shows the estimated amount of paint needed for average-sized rooms.

One gallon of typical latex paint usually covers 350 to 400 square feet of wall area.

This does assume that the paint you are using can cover in one coat. If you are going from light to dark or dark to light, you may need either a tinted primer and one to two coats of paint or two to three coats of paint without primer to get the desired color.

How to Measure a Room

Using a reference table is quick and easy, but the most accurate method of calculating paint and primer for a project is to measure the surfaces to be painted and use the coverage estimate for the specific product you’re using.

Step One: Measure the Walls

The first step in estimating paint material is to measure the walls or ceilings you will be covering. Measure the length and height of each wall in feet and write them down. It may be easiest to round up to the next foot measurement for measurements that contain partial feet.

You can also measure the walls in inches and convert the area to square feet later for more accurate measurements, particularly in small spaces, closets, or small bump-out walls.

Step Two: Calculate Square Footage of Each Surface

The next step in the process is to calculate the square footage of the walls and ceilings. Square footage is an area measurement of a space, measured in feet, and we have a simple calculator to help with these calculations.

For each set of measurements from step one, multiply the width and height together to get the square footage.

If you measure in inches, divide the number you get from multiplying by 144 to convert to square feet. If doing this method, it is sometimes easiest to add up the square inches from each area first, then convert to square feet. Write down the square footage of each wall.

Step Three: Add Square Footages Together to Find the Total

Once you know the square footage of each wall, add them together to find the total square footage. If you had split complex walls into several surfaces, then be sure to add each surface to get the total.