Drywall Calculator
Calculate how many drywall sheets and supplies you need.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Drywall Calculator
Enter your room dimensions and the calculator instantly shows how many drywall sheets to buy, along with joint compound, tape, and screw estimates. Here is how to get an accurate count:
- Enter the room dimensions. Type the length, width, and wall height in feet. A standard residential ceiling height is 8 feet, but 9 and 10 foot ceilings are common in newer construction.
- Check "Include ceiling" if needed. This adds the floor area (length times width) to your total. Leave it unchecked if the ceiling is already drywalled or if you are just patching walls.
- Enter doors and windows. The calculator subtracts 21 square feet per door and 15 square feet per window from the gross wall area. These are standard rough-opening estimates. Adjust the count to match your actual openings.
- Choose your sheet size. Standard 4x8 sheets (32 sq ft) are easiest to handle solo. 4x10 and 4x12 sheets reduce the number of horizontal seams on tall walls but require two people to lift.
- Set a waste factor. The default 10% covers cut waste at corners and around openings. Increase to 15% for rooms with many angles, archways, or if you are new to hanging drywall.
- Read your results. The primary number is sheets with waste, which is what you should actually buy. The breakdown shows net area, joint compound in gallons, tape rolls, and screw weight.
Use the Share button to send your estimate to a contractor or lumber yard, or Copy to paste it into a shopping list.
About the Drywall Calculator
Drywall, also called sheetrock or wallboard, is the most common interior wall surface in North American construction. A standard 4x8 sheet covers 32 square feet and weighs about 57 pounds for half-inch thickness. Half-inch (1/2") drywall is used for most interior walls and ceilings. Five-eighths inch (5/8") Type X is required for fire-rated assemblies such as garage walls and certain shared walls.
This calculator uses the standard estimating approach: perimeter (length plus width, times two) multiplied by wall height gives gross wall area. Ceiling area is added optionally. Door and window rough openings are subtracted. The net area is divided by the sheet area and rounded up to whole sheets, then increased by the waste factor. Joint compound consumption is based on approximately 0.053 gallons per square foot for three coats, which is the standard finish process. Tape usage runs one roll per 500 square feet of net area. Screw quantity is based on approximately 32 screws per sheet at standard field and edge spacing, with roughly 150 screws per pound of drywall screws.
Frequently Asked Questions
How many sheets of drywall do I need for a 12x14 room with 8-foot ceilings?
A 12x14 room with 8-foot ceilings has a gross wall area of 2 × (12 + 14) × 8 = 416 square feet. Subtract two standard doors (42 sq ft) and three windows (45 sq ft) to get a net area of about 329 square feet. Using 4x8 sheets and a 10% waste factor, you need approximately 12 sheets. Adding the ceiling (168 sq ft) brings the total to about 18 sheets with waste.
What thickness of drywall should I use?
For most interior walls and ceilings, 1/2-inch drywall is the standard choice. It balances weight, cost, and sound attenuation for typical residential use. Use 5/8-inch Type X drywall anywhere a fire rating is required, such as the wall between an attached garage and living space, or between units in a multi-family building. For curved walls or arches, 1/4-inch flexible drywall bends to radius without cutting. Cement board is used behind tile in wet areas like showers, not standard drywall.
How much joint compound do I need per sheet of drywall?
A typical three-coat finish (tape coat, second coat, finish coat) uses approximately 0.053 gallons of joint compound per square foot of drywall. A standard 5-gallon bucket covers about 480 square feet per coat, so a three-coat job consumes roughly one 5-gallon bucket per 160 square feet. For a room with 329 square feet of net drywall area, plan on about 2 to 3 five-gallon buckets depending on how many coats you apply and how thickly you spread. Pre-mixed all-purpose compound is the most common choice for DIY work.
Should I hang drywall vertically or horizontally?
On walls with standard 8-foot ceilings, horizontal hanging (long edge perpendicular to studs) is usually preferred because it reduces the total length of seams, places the butt joint (the non-tapered edge) near the middle of the wall where it is easier to feather, and adds structural rigidity. On walls taller than 8 feet, vertical hanging is often more practical because it avoids horizontal seams that cross studs. Ceilings are always hung with the long edge perpendicular to joists. Local codes and your specific framing layout may also influence the decision.