A little math goes a long way
Most residential installations use 4-by-8-foot sheets of drywall.
To get the right number of sheets, find the total square footage of your project.
Divide the project square footage by the square footage of the sheet.
Round up and add 10% to 15% to the total to account for odd cuts.
If you’re planning a renovation, you may wonder how much drywall you’ll need to finish the walls. Drywall installation is an essential step in the process, and if you underbuy, you risk project delays. The good news is that you don’t have to be a pro to get a solid estimate. This guide covers some simple math for determining how much drywall you need.
Drywall, which you may know as Sheetrock® or gypsum board, is sold in sheets or panels in different sizes and thicknesses. You’ll choose between three separate sizes:
4-by-8-foot: Most residential projects use 4-by-8 sheets that are ½ inch thick. This is the standard option that covers 32 square feet. You can hang this type of drywall vertically or horizontally.
4-by-12-foot: This size is ideal for tall or long walls and covers 48 square feet. If you have tall walls, a larger size allows you to hang a single sheet from floor to ceiling.
4-by-16-foot: A 4-by-16 sheet covers 64 square feet. Installation is not a solo job for this size. You’ll need a few people to help, but it can cover longer and taller walls, making it easier to give large spaces a seamless look.
Most homeowners prefer to hire a local drywall installer to handle their installation. A pro can determine how much drywall you need for your project. That said, if you plan to DIY, you don’t need a drywall calculator—you just need to take measurements and do some math.
Follow these steps to calculate how much drywall you need for your project:
Find the area's square footage: Use your tape measure to measure the length and width of each wall you plan to cover. Multiply the total length by the total width to get the total square footage for your project.
Account for openings: Use the same method to obtain the square footage of windows and or doors in your installation area. Subtract the square footage of these openings from your project total.
Add 10% to 15% to the total: It’s a good idea to add 10% to 15% to your total to account for awkward cuts and waste.
Determine the number of drywall sheets needed: To get the total number of sheets, divide the total square footage of your project by the square footage covered by the sheet. First, you’ll have to choose the size of the sheet. Unless you have tall ceilings, you’ll probably want to use 4-by-8 sheets, which cover 32 square feet each.
Here’s an example: You need to cover 550 square feet, which includes some extra for odd cuts. If you’re using standard 4-by-8 sheets that covers 32 square feet each, your calculation should look like this:
550 ÷ 32 = 17.19
Since you must purchase whole sheets, you can round up to 18 sheets of drywall in total.
For most homeowners, drywall installation costs $1,000 to $3,200. If you have experience, you can cut out some of the labor costs by hanging the drywall yourself. Remember, you’ll probably need a few helping hands, especially if you go with a larger size.
In that case, you’ll need a bit more materials than just the drywall. Here’s how you can estimate the amount of materials you’ll need during the installation.
To get an estimate of the amount of drywall tape you’ll need, find out how many linear feet are in the perimeter of a sheet of drywall. Add the length of each side together to get the total linear feet for your project. Here are the perimeter measurements for the most common sizes of drywall sheets:
A 4-by-8-foot sheet has a 16-foot perimeter
A 4-by-12-foot sheet has a 32-foot perimeter
A 4-by-16-foot sheet has a 40-foot perimeter
Multiply the total linear feet of the perimeter by the total number of sheets you plan to use. The answer is the total linear feet of drywall tape you need to purchase.
You’ll need to purchase 0.053 pounds of joint compound (or drywall mud) per square foot of drywall. To calculate how much you need, multiply your project's total square footage by 0.053 pounds. This is only an estimate, so round up to be safe.
There’s a huge debate on drywall screws versus nails. Nails hold better, and you’ll have to space them carefully. However, you’ll need more nails to get the job done. As a general rule, you’ll need about one screw for every square foot of drywall. A standard 4-by-8-foot sheet of drywall requires 32 screws.
Corner beads are 8 or 10 feet long, and you’ll need one for each wall corner. You’ll also need to put corner beads in the corners of certain structures like soffits or window ledges.
The number of corner beads depends on the length of the corners. You may have to cut an 8- or 10-foot corner bead to size, so make sure you have enough linear feet of material to work with.
To do this, add up the length of all the corners of wall structures. Add a few inches to the final measurement to account for cutting and overlap. Divide that number by 8 or 10 feet to figure out how many corner beads you’ll need. It's better to have too much material than too little.
