How to Measure Walls for Painting [Expert Guide]

Randy Charles
Professional Painter

Randy Charles is the owner of PaintCentric.com, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years...Read more

Ever wondered how to measure walls for painting? It sounds simple, but getting it right is not always easy. Measuring walls is more than just length and height. You must consider doors, windows, and other features. These can make measuring tricky. You want to avoid common mistakes, like under or overestimating the space. This can lead to not enough or too much paint.

Here’s a full step-by-step guide on How to Measure Walls for Painting

Tools Needed for Measuring Walls

To start, gather the necessary tools. You’ll need:

  1. A tape measure – for measuring the dimensions of the walls.
  2. A ladder – to reach high areas.
  3. A notebook and pen – for noting down measurements.
  4. A calculator – for calculating areas and paint requirements.

Measuring Wall Width and Height

How To Measure Walls For Painting Expert Guide

Accurately measuring the width and height of your walls is a crucial step in any painting project. This process, while straightforward, demands careful attention to ensure precision in your measurements. Here’s a detailed approach to measuring your walls correctly:

1. Measuring Wall Width

To measure the width of a wall, you’ll need a reliable tape measure. Start by positioning one end of the tape measure at one corner of the wall. Extend the tape measure across the wall to the opposite corner, keeping it as straight and level as possible. This step is essential to avoid any inaccuracies that could arise from a sagging or angled tape measure.

If the wall is wider than your tape measure, take measurements in sections. Measure up to a point you can reach, mark it, and then continue from that point to the end of the wall. Add these measurements together for the total width. Make sure to write down each measurement to avoid forgetting or mixing them up.

2. Measuring Wall Height

For measuring the height of the wall, start from the floor and extend your tape measure straight up to the ceiling. If the ceiling is high and out of reach, use a sturdy ladder to get closer to the ceiling. Safety is paramount here, so ensure the ladder is stable and firmly positioned before climbing.

Measure in one smooth motion, if possible, to avoid breaks in the measurement. Just like with the width, if you can’t measure the height in one go, do it in manageable sections and add them together.

3. Dealing with Irregular Wall Shapes

Walls are not always perfect rectangles. If your wall has alcoves, recesses, or protrusions, measure these areas separately. For alcoves or recesses, measure their width and height as you would with the main wall area. For protrusions, measure the height and depth. These measurements help in calculating the extra paint needed for these irregular areas.

When dealing with slanted walls, like those in attics or under staircases, measure the highest and lowest points of the wall. Calculate the average height for these walls to estimate the area more accurately.

4. Accounting for Windows and Doors

Windows and doors take up space that doesn’t need painting, so you must subtract their area from the total wall area. Measure the height and width of each window and door. Multiply these to get the area of each, then add up the areas of all windows and doors. Subtract this total from your overall wall area calculation.

For instance, if a door measures 7 feet in height and 3 feet in width, its area would be 21 square feet (7 feet x 3 feet). If this is the only door or window on the wall, you would subtract 21 square feet from the total wall area.

Calculating Wall Area

Once you have the measurements of your walls, the next step is to calculate the total area that needs painting. This is a simple yet important step to determine how much paint you will need.

Multiply Width and Height:

For each wall, multiply the width by the height to find its area. This calculation gives you the square footage of each wall. For example, if one of your walls is 12 feet wide and 9 feet high, the area of this wall is 108 square feet (12 feet x 9 feet). It’s crucial to perform this calculation for each wall individually to get accurate results.

Add All Areas Together:

After calculating the area of each wall, add these figures together. This sum is the total area of the walls in your room. Adding these areas gives you a comprehensive view of the space you will be painting.

Subtract Windows and Doors:

Don’t forget to subtract the areas of windows and doors from your total wall area. Since you won’t be painting these areas, they should not be included in your final paint area calculation. Measure each window and door, multiply the width by the height to find their areas, and subtract this from your total wall area.

For instance, if you have a door that measures 7 feet by 3 feet, its area is 21 square feet. If this is the only door on the wall, you would subtract 21 square feet from your total wall area.

Measuring for Trim and Ceilings

While the walls are your primary focus, trims, baseboards, and ceilings are also important parts of the painting project. These areas often require different types of paint and therefore should be measured separately.

  1. Trims and Baseboards: Measure the length of each piece of trim or baseboard. Then, measure its width. Multiply these two numbers to find the area of each trim or baseboard. If you have several pieces of trim or baseboard, do this calculation for each and then add them together. The sum is the total area of trims and baseboards that will need painting.
  2. Ceilings: Ceilings require a separate calculation because they may need a different type of paint, especially if they are textured. Measure the length and width of the ceiling. Multiply these figures to get the area of the ceiling. For instance, a ceiling that is 12 feet long and 9 feet wide has an area of 108 square feet.

Note that if your ceiling has any fixtures or fittings that will not be painted, like a ceiling fan or decorative moldings, you should subtract their area from the total ceiling area.

  1. Recording Measurements: Keep a detailed record of all these measurements. This record will be invaluable when you are buying paint and supplies. It ensures that you purchase the right amount of paint for each part of your room – walls, trims, baseboards, and ceilings.

Estimating Paint Quantity

Once you have calculated the total area of the walls you will paint, the next step is to figure out how much paint you need. This part is crucial because having the right amount of paint ensures that you can complete your project without unnecessary interruptions.

Check Paint Coverage Information:

Every paint can have information about how much area it can cover. This coverage is usually given in square feet per gallon. For example, a paint can might say that it can cover up to 350 square feet. This number is important because it tells you how much area you can paint with one gallon of that particular paint. Remember, different paints have different coverage rates. Some might cover more area, some less, depending on their quality and type.

Calculate Paint Needed Based on Total Area:

To find out how much paint you need, take the total area of your walls and divide it by the coverage rate of the paint you’ve chosen. For instance, if the total area of your walls is 1000 square feet and the paint covers 350 square feet per gallon, you will need approximately 2.86 gallons of paint. Since you can’t buy 0.86 of a gallon, round up to the nearest whole number, which in this case would be 3 gallons.

Account for Multiple Coats:

Often, you might need to apply more than one coat of paint for a smooth, even finish. If you plan to do multiple coats, you’ll need more paint. A good rule of thumb is to double the amount for two coats. However, this can vary depending on the color you’re covering and the color you’re applying. Dark colors might need more coats to cover a light wall, and vice versa. Additionally, if you’re painting over a dark color with a light one, using a primer can reduce the number of coats of paint needed.


Accurately measuring your walls for painting is a crucial step that ensures a smooth and successful painting project. It helps in avoiding the wastage of resources and time. By following the steps outlined in this article, you can confidently measure your walls and estimate the amount of paint needed

Randy CharlesProfessional Painter

Randy Charles is the owner of PaintCentric.com, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years of experience in the painting industry, Randy has become an expert in the field and is passionate about helping others learn more about painting. He has written numerous articles on the subject and is committed to providing accurate and up-to-date information to his readers.

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