Painting your home’s exterior can transform the look and curb appeal of your property. With exterior paint prices up 30% since 2021, buying the correct amount of paint is more important than ever. If you’re planning to do it yourself, use an online paint calculator to enter the measurements of your home and estimate the number of gallons you’ll need.

Whenever I paint my home or rental properties, I always start with a paint calculator to avoid the costly mistake of buying too much paint. Here I’ll give you tips to measure your home accurately, step-by-step instructions on how to use a paint calculator, and my recommendations.

Benefit of Using a Paint Calculator

Saves time;Saves money;Environmentally friendly;DIY-friendly.

How To Measure Your Home’s Exterior

No matter which paint calculator you use, start by measuring your home’s exterior. You’ll need a tape measure, calculator, paper and pencil.

To begin, draw one side of your house as a group of triangles, rectangles and squares. If you have a gable roof, one side of your house will be a square and a triangle to account for the peak. Measure the length and height of each shape, then round up to the nearest foot. Calculate the area of each shape and add them for the side’s total area.

Pro tip: To calculate the square footage of squares and rectangles, multiply length by height. For triangles, multiply length by height, then divide by two.

Next, measure all windows and doors on this side of the house and determine their total square footage, then subtract that from the total area measurements of the side. This will give you the square footage of the area that will require paint.

Repeat this process for all sides of your house to get the total. If you use a paint calculator that only requires linear measurements, you now have these numbers as well.

How To Use an Exterior Paint Calculator

Open the paint calculator website. I couldn’t find any reliable paint calculator apps geared toward homeowners. Any useful ones I found were for professionals and required a subscription.Fill out all fields pertaining to your home with the measurements you gathered.Hit ‘calculate’ and wait for the number of gallons to generate.

Exterior Paint Calculator Mistakes To Avoid

Most paint calculators feature settings for ‘interior‘ and ‘exterior,’ so make sure to select ‘exterior’ before entering your information.Don’t forget to subtract windows and doors, and any unpainted surfaces like chimneys or stone faades.If you plan to paint any outbuildings, like a shed or garage, make sure to include them in your calculator entries as well.Most exterior paint calculators will generate their estimate based on one coat of coverage. If you plan to do two coats, double the number before heading to the paint store.

Great Paint Calculators

Look for a paint calculator lets you to customize your estimate and has fields for a variety of information and measurements. Avoid ones that refer to general measurements like “small” or “large” to describe your house, or rely on interior square footage only.

Sherwin-Williams offers a great paint calculator that gathers detailed information, including the texture of your siding, which impacts the amount of paint needed for adequate coverage. It also lets you add a side at a time, great for homes with additions or bump out sections. It takes into account sides with peaks, and you can subtract windows, doors and trim for each side as well.

Valspar offers a thorough exterior paint calculator. It gathers information about each side of your house, and even offers a separate field for peak height. It also has an in-depth trim calculator that accounts for trim length and width.

Dutch Boy’s exterior paint calculator is best suited for a quick estimate. It doesn’t ask for a lot of details, but does account for siding texture and the number of windows and doors. If you’re looking for a ballpark number, this one will do fine.

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