How many sheets of drywall do you need?
Add your rooms or walls, pick ceiling or not, get sheet counts and cost instantly.
How do I calculate how much drywall I need?
Add up the wall area — the room's perimeter times the wall height — plus the ceiling, add 10 to 15% for cuts, then divide by the area of one sheet: 32 square feet for 4×8, 40 for 4×10 and 48 for 4×12. A 12 by 12 ft room with 8 ft walls has 384 square feet of wall and a 144 square foot ceiling: 528 square feet, about 581 with 10% extra — 19 sheets of 4×8 or 13 sheets of 4×12.
What size drywall sheets should I buy?
4×8 sheets are the easiest to carry, fit in a pickup and suit one-person jobs. 4×12 sheets cover 50% more with fewer seams, so there is less taping and sanding, but they need two people. For 9 ft walls, 54-inch-wide sheets hung sideways cover the height in two rows.
Should I subtract doors and windows?
Usually not for drywall. The sheets are hung across small openings and cut out afterwards, and the offcuts rarely fit anywhere else. Subtract only big openings such as patio doors or a garage door — this calculator starts with none, so add them if you need to.
How much extra drywall should I buy?
About 10% for simple rectangular rooms, and 15 to 20% for rooms with angled walls, vaulted ceilings or lots of cutouts. A spare sheet or two also covers the one that gets cracked on the way in.
What thickness of drywall do I need?
Half-inch drywall is standard for interior walls. Five-eighths-inch Type X is used where fire resistance is required, such as the wall and ceiling between a garage and the house, and on ceilings with joists 24 inches apart, where thin board can sag. Check your local building code.
Worked example: a 14 by 12 foot bedroom
Walls: the perimeter is 2 × (14 + 12) = 52 feet, and at 8 feet high that is 416 square feet. The ceiling is 14 × 12 = 168 square feet, so the total is 584. With 10% extra for cuts that becomes 642 square feet. Divided by 32 square feet per 4×8 sheet it is 20.1, so buy 21 sheets; with 4×12 sheets (48 square feet) it is 13.4, so 14. With 20% extra for a room with many angles the 4×8 count rises to 22. Always round up, because a partial sheet cannot be bought, and never add the extra to each wall separately and then again to the total.
How far apart can the framing be for each thickness?
The Gypsum Association's application standard, GA-216, sets a maximum framing spacing for single-layer panels. On walls, 3/8 inch board needs framing no more than 16 inches on center, while 1/2 and 5/8 inch board allow 24 inches. On ceilings, 1/2 inch board hung across the joists (perpendicular) allows 24 inches, but hung along them (parallel) only 16 inches, and 5/8 inch board allows 24 inches across the joists and 16 along them. The 3/8 inch board is limited to 16 inches on ceilings and must not carry insulation. Ceilings that will get water-based texture have stricter rules, so check the standard or the board maker.
How many screws will I need?
The count follows from the spacing, not from the sheet size. GA-216 allows screws no more than 12 inches apart on ceilings and 16 inches apart on walls when the framing is 16 inches on center, and 12 inches apart on both when the framing is 24 inches on center. Buy a box of screws with some margin rather than counting an exact number, and use screws long enough to reach well into the framing, as the standard requires.
Common drywall estimating mistakes
Measuring the room but forgetting the ceiling. Adding waste twice, once in the area and once again in the sheet count. Rounding up wall by wall instead of once for the whole job, which buys a sheet more than needed for every wall. Forgetting to subtract a large opening such as a patio door, which this calculator does not do unless you enter it.
Sources and related calculators
Sources: Gypsum Association, GA-216, Application and Finishing of Gypsum Panel Products (Table 1 for maximum framing spacing and Section 5.4 for screw spacing); sheet sizes are the common US sizes of 4×8, 4×10 and 4×12 feet. Building codes and the board maker's instructions have the final say. Related: paint calculator, stud layout calculator, insulation calculator and plywood calculator.