Drywall Calculator
Estimate drywall sheets for walls and ceilings from the total area or the room size (minus doors and windows), with waste, plus screws, joint compound, tape, corner bead, board weight and the material and installed cost.
How it works
board area = total area, or 2 × (length + width) × height − doors − windows (+ ceiling = length × width) · sheets = ⌈area × (1 + waste%) ÷ sheet area⌉, walls and ceiling counted separately · screws per sheet = framing members crossed × (⌊sheet width ÷ screw spacing⌋ + 1), + 10% spare · joint compound ≈ 10 gal per 1,000 sq ft × (1 + waste%) · tape ≈ 375 ft per 1,000 sq ft
Start from the surface you will cover. Either enter the total area, or enter the room: the walls are the perimeter, 2 × (length + width), times the wall height, less the doors and windows, and the ceiling is the length times the width. Divide by the area of one sheet (32 sq ft for a 4 × 8) and round up after adding a waste allowance for cutouts and offcuts; walls and ceilings are counted separately because they are cut separately and the ceiling is often a different board. Screws come from the framing: a sheet hung across the studs gets a row of screws on every stud it crosses, typically every 16 inches on walls and every 12 inches on ceilings, which is about 28 screws for a 4 × 8 on a wall and 35 on a ceiling at 16 in framing. Joint compound for a standard Level 4 finish runs about 10 gallons of ready-mixed all-purpose per 1,000 sq ft of board, and tape about 375 ft per 1,000 sq ft. Longer sheets cover the same area with fewer butt joints, which means less taping and a flatter wall.
Worked example
1,000 sq ft in 4 × 8 sheets with 10% waste: 1,000 × 1.10 = 1,100 ÷ 32 = 34.4, rounded up to 35 sheets (32 for the exact area). On walls with studs at 16 in and screws every 16 in, each sheet takes 7 × 4 = 28 screws, so 1,000 ÷ 32 × 28 × 1.1 ≈ 963 screws, about 3.2 lb of 1-1/4 in screws. Joint compound is 1,000 × 0.01 × 1.1 = 11 gal, three 4.5 gal pails, and tape 375 ft, one 500 ft roll. At $15 a sheet the board costs $525, and the materials about $615 in all with screws at $6 a pound.
Sources: USG Sheetrock All Purpose Joint Compound submittal (≈ 10 gal per 1,000 sq ft) · Lowe’s Drywall Materials Estimator (sheets, compound, tape and fasteners per 100–1,500 sq ft) · National Gypsum drywall materials calculator
Frequently asked questions
How many sheets of drywall do I need for a 12 × 14 room?
With 8 ft walls the walls are 2 × (12 + 14) × 8 = 416 sq ft. Take off a door (21 sq ft) and two windows (30 sq ft) and you have 365 sq ft, or 13 sheets of 4 × 8 with 10% waste. The 168 sq ft ceiling adds 6 more, so about 19 sheets in all. Choose Room size to get this with your own measurements.
Which sheet size should I use?
Longer 4 × 10 or 4 × 12 sheets hung horizontally cut the number of butt joints, giving a flatter, easier finish, but they are heavy (a 1/2 in 4 × 12 weighs about 77 lb) and hard to carry up stairs or turn in tight rooms. 54 in wide board covers a 9 ft wall in two rows. Pick the largest sheet you can actually move and lift.
What thickness of drywall goes where?
Half-inch is standard for walls; 5/8 in Type X is used on ceilings (it sags less) and where a fire rating is required, such as a garage wall next to living space. Quarter-inch and 3/8 in board are for curves and for covering old walls. Local code decides the fire-rated locations.
How many screws per sheet of drywall?
A 4 × 8 sheet hung across studs at 16 in crosses 7 studs. With screws every 16 in on a wall that is 4 per stud, or 28 per sheet; with screws every 12 in on a ceiling it is 5 per joist, or 35. Closer spacing or 24 in framing changes the count, which you can set under More options. A pound of 1-1/4 in drywall screws holds roughly 300.
How much joint compound and tape?
About 10 gallons of ready-mixed all-purpose compound per 1,000 sq ft for tape plus two coats, so roughly a third of a gallon per 4 × 8 sheet, and about 375 ft of tape per 1,000 sq ft. A Level 5 skim coat roughly doubles the compound; the drywall mud calculator covers other compounds and finish levels.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.