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4 Easy Way to Calculate Painting Cost with For Walls using Paint Calculator

4 Easy Way to Calculate Painting Cost with For Walls using Paint Calculator

How Much Paint Do I Need

There are a thousand shades of paint color and many paints manufacturer. Before you start painting your walls, the last thing you want to do is run out of paint and then try to find the same color back on the shelves of your home improvement retailer. Here are 4 Easy Way to Calculate Painting Cost with For Walls using Paint Calculator.


Deciding how much paint you need for your project is one of the essential aspects of your project…and we have provided a quick and easy guide to show you exactly how much paint you need.

Before you start, you will need a tape measure, a calculator (unless you want to do the maths on paper), as well as a pen and a piece of paper.

How Much Paint?

As a general rule, to achieve a one-coat coverage of an interior wall, paint should be applied at a maximum of 400 square feet per gallon. If your walls are rough (like exposed brickwork) or textured (like wood paneling), you should allow for 25-30 square feet per gallon. Further, some bright colors may require 1-3 coats for the color to really stand out as it should.

Calculate – For Walls

1)  Measure the length of each wall and add the numbers together.

Example: 24ft + 15ft + 24 ft + 3ft = 66 total feet

2)  Next, measure the height of the wall and multiply this by the total length number in step one to get the total square feet of the room.

Example: 66 total feet in length x 12 feet (height of wall) = 792 square feet

3)  Now, so that you don’t purchase too much paint, you will need to subtract the square footage of the doors and windows.  Don’t worry it’s easy to do, just follow the rules below.

For each door subtract 20 square feet from the total square feet

For each window subtract 15 square feet from the total square feet

Example: let’s say you have 2 windows and one door in the room. You would

Make this calculation:

792 total square feet – 30 square feet (two windows at 15 square feet per window) – 20 square feet (one door) = 742 square feet

4. Finally, divide the total square feet (minus doors and windows) by 400 (the maximum square foot coverage for one coat of paint)

This will give you the number of gallons of paint you will need for your project

Example: 742 total square feet / 400 (maximum coverage) = 1.85 gallons of paint.

Important: If you think you will be applying more that one coat of paint (very common), make sure you double the gallons of paint needed for your project.

Notes: When You Are Ready to Buy Your Paint, It Is a Good Idea to Do the Following:

1)  Buy a little extra paint

2) If you are having a color mixed for you, make sure the retailer writes down the mixture on the can

3) If you are buying off the shelf paint, write down what color it is and who the manufacturer is so you can get the same in the future

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