Professional Drywall Estimator
Estimated Materials
How to Calculate Drywall Needed
Planning a renovation or finishing a basement requires a precise material list to avoid multiple trips to the hardware store or excessive waste. Calculating drywall isn't just about the walls; you must account for ceilings, waste from cuts, and the specific size of the boards you intend to use.
Step 1: Calculate Total Square Footage
To find the surface area of your walls, multiply the total length of all walls by the ceiling height. If you are also drywalling the ceiling, calculate its area by multiplying length by width and add it to your wall total. Do not subtract windows and doors unless they are exceptionally large (over 4 feet wide), as you usually buy drywall to cover them and cut out the openings.
Step 2: Choose Your Sheet Size
Drywall typically comes in three standard sizes:
- 4′ x 8′: The most common size, easy for one person to handle.
- 4′ x 10′: Good for 10-foot ceilings to avoid horizontal seams.
- 4′ x 12′: Best for long walls to reduce the number of vertical joints.
Step 3: Account for Waste
Standard professional practice is to add a 10% waste factor. If the room has many alcoves, vaulted ceilings, or odd angles, increase this to 15%. For a simple square room, 5% may suffice.
Estimation Formulas Used
Our calculator uses the following industry-standard approximations for accessories:
- Joint Compound: Approximately 0.05 pounds of ready-mixed mud per square foot of drywall.
- Joint Tape: Approximately 0.15 linear feet of tape per square foot of drywall.
- Screws: Roughly 1 screw for every square foot of drywall (assuming 12-inch spacing on studs).
Example Calculation
If you have a room with 40 linear feet of wall at 8 feet high, your wall area is 320 sq ft. Adding a 150 sq ft ceiling brings the total to 470 sq ft. With a 10% waste factor, you need to cover 517 sq ft. Using 4×8 sheets (32 sq ft each), you would need 16.15 sheets, which you would round up to 17 sheets.