Using a paint calculator is an easy and efficient way to estimate how much paint you’ll need for your walls. Simply input the dimensions of the walls you plan to paint, including height and width, and the calculator will give you an accurate estimate based on typical paint coverage rates. It takes into account factors like the type of paint, the number of coats, and the room’s layout to ensure you’re not over- or under-buying.
Disclaimer: These estimates are based on standard conditions and coverage rates. The exact amount of paint you need may vary depending on factors like surface texture, color, and application technique. We recommend purchasing a little extra to account for touch-ups and potential variations in your specific project.
How to Use a Paint Coverage Calculator
Accurate measurements are key when determining how much paint you need. To measure your walls correctly, you’ll need a tape measure. Start by measuring the length and height of each wall. Multiply these dimensions to get the total square footage of each wall. If you have multiple walls, repeat this process for each one and then add the total square footage together for an overall number. Keep in mind that you’ll also need to adjust for doors and windows (which we’ll cover next).
How to Measure Your Walls For Painting
Step-by-Step Guide to Estimating Paint Needs
Measure Your Walls
Tools Needed: To get started, you’ll need a measuring tape, calculator, and possibly a helper for longer walls. First, measure the length of each wall, then measure the height. Multiply the two numbers together to get the square footage for that wall. Repeat this for all the walls you plan to paint, then add them all up to get the total square footage. This will give you an estimate of the amount of paint needed.
Calculating Wall Surface Area (Length × Height)
Multiply the length by the height for each wall to calculate the total square footage. For example, if your wall is 12 feet long and 8 feet high, the total square footage for that wall is 96 sq. ft.
Subtract Windows and Doors
Windows and doors take up valuable space, so subtract their square footage from the total wall area. Standard window sizes are around 15-20 sq. ft., and doors are usually about 20 sq. ft. By subtracting these areas, you’ll get a more accurate idea of how much paint is needed. If you have unusual window sizes or multiple doors, make sure to measure them individually for precision.
Standard Sizes and How to Subtract Them from Total Square Footage
For standard-sized doors (typically 30” x 80”) subtract 20 sq. ft., and for windows, subtract about 15-20 sq. ft., depending on their size. If your windows are larger, you may need to measure them individually to get a more accurate estimate.
Understand Paint Coverage
Each gallon of paint covers a specific area, usually 350-400 sq. ft. for interior walls, depending on the brand and type of paint. It’s important to understand that different paint types, like flat or semi-gloss, may have slightly different coverage rates, so always check the label on your paint can for precise information.
Average Coverage per Gallon
A gallon of paint typically covers about 350 sq. ft. for smooth surfaces, but this can vary depending on factors like texture and color. Darker colors, in particular, may require more paint due to their ability to absorb light.
Differences by Paint Type or Brand
The brand and type of paint you choose can affect coverage. High-quality paints tend to have better coverage and may require fewer coats. In some cases, if you are using high-quality paint, you may be able to get away with one coat instead of two. Always check the specifications on the paint can for details on coverage per gallon.
Factor in Number of Coats
Most painting projects require at least two coats of paint to achieve the best finish and durability. Don’t forget to account for primer as well—especially when painting new drywall or darker colors, as this will help improve coverage and reduce the number of coats needed.
Primer + Paint
Primer is essential when painting over porous surfaces or when making a dramatic color change. A primer helps create a better surface for the paint to adhere to, ensuring a more even coat and preventing colors from bleeding through.
Dark vs. Light Colors
Dark colors tend to require more coats because they can be harder to cover, especially when transitioning from a lighter color. Lighter colors usually cover better, but you may still need a second coat to achieve full opacity.
New Drywall Considerations
If you’re painting new drywall, it’s important to use a primer first. Drywall is porous and will absorb paint differently than previously painted surfaces, meaning you’ll need more paint overall.
How Many Square Feet Does A Gallon of Paint Cover?
On average, one gallon of paint covers about 400 sq. ft. for interior walls. However, this can vary depending on the type of paint and the surface being painted. Exterior projects may cover less area, around 350 sq. ft. per gallon, and when using primer, it’s common to cover only 200 sq. ft. per gallon.
| Surface Type | Coverage per Gallon | Coats Needed | Additional Notes |
|---|---|---|---|
| Interior Walls (Smooth) | 350-400 sq. ft. | 2 Coats | Standard coverage for most interior walls. |
| Interior Walls (Textured) | 300-350 sq. ft. | 2 Coats | Textured surfaces absorb more paint, requiring more coverage. |
| Exterior Walls | 350 sq. ft. | 2 Coats | Exterior walls are often more porous, requiring slightly more paint. |
| New Drywall | 200-250 sq. ft. (Primer) | 2 Coats (Primer + Paint) | New drywall requires primer before applying paint. |
| Darker Colors (Interior) | 300-350 sq. ft. | 3 Coats | Dark colors may need extra coats for full coverage, especially over lighter shades. |
| Light Colors (Interior) | 350-400 sq. ft. | 2 Coats | Light colors generally require fewer coats. |
| Primer | 200 sq. ft. | 1 Coat | Primer helps with adhesion and coverage for bare surfaces. |
Factors That Affect How Much Paint You Need
Several factors can influence the amount of paint you need, such as:
- Wall texture: Rougher walls absorb more paint, requiring additional coats.
- Paint color: Lighter colors may require fewer coats than darker shades.
- Surface type: Newly drywall or repairs may require extra primer.
- Paint type: Different paints have varying coverage rates.
How Much Primer Do I Need?
Priming is essential for achieving a smooth and long-lasting finish, especially when painting over bare wood or new drywall. The amount of primer you need depends on the surface area being covered and the type of surface. As a general rule, one gallon of primer covers approximately 200 sq. ft.
How Much Paint Do I Need To Paint A House Exterior?
Painting the exterior of a house requires careful consideration. A gallon of paint typically covers around 350 sq. ft. for exterior walls. Consider the size of your home, the number of stories, and the condition of the surfaces when estimating the paint quantity.
Tips to Avoid Overbuying or Running Out Of Paint
To avoid having too much paint and running out of paint, always estimate your paint needs based on surface area rather than simply guessing. Use a paint calculator for accuracy, and be sure to account for the number of coats required. It’s always a good idea to buy a little extra paint for touch-ups, but don’t over-purchase if you’re unsure.
Should I Hire a Professional Painter?
While DIY painting is an option, hiring a professional painter like Tuck HS ensures high-quality results and saves you time. Tuck HS has the tools, expertise, and experience to handle both interior and exterior painting projects—from prep to clean-up. Whether you’re refreshing a single room, updating your home’s exterior, or repainting the entire house, Tuck HS delivers a smooth, stress-free experience with flawless results. With Tuck HS, your painting project will be completed with precision and care, giving your home the perfect finish it deserves.