Enter your room size and pick the sheet you are buying - 4×8 or 4×12 - to get the drywall sheets, screws, joint compound and tape for the job. Sized for the boards Lowe's stocks.
Openings (deducted from walls)
Boarded area
472.0 sq ft
Screws
~544
Joint compound
~62 lb · 475 ft²/box
Joint tape
~175 ft
This is the standard drywall calculator set up for the sheet sizes Lowe’s carries. It sizes both the boarding and the finishing from your room dimensions:
wall area = 2 × (length + width) × height
ceiling = length × width (if you board it)
sheets = ceil( (wall area + ceiling) × wastage ÷ sheet area )
screws = sheets × 32
compound = boarded area × 0.64 kg/m²
tape = boarded area × 1.2 m/m²
It treats the room as a closed box and lets the wastage allowance cover the offcuts around doors and windows - or add each opening to deduct it exactly. Boarding more than one room? Add a room for each and the sheets, screws, mud and tape total into one order. All math runs in exact metric internally, so switching units never changes the answer.
| Board | Size | Area | Use |
|---|---|---|---|
| 1/2 in standard | 4 × 8 ft | 32 sq ft | Walls and ceilings in most rooms |
| 1/2 in standard | 4 × 12 ft | 48 sq ft | Long walls - fewer joints to tape |
| 5/8 in Type X | 4 × 8 ft | 32 sq ft | Fire-rated walls, garages, ceilings |
| 1/2 in mold-resistant | 4 × 8 ft | 32 sq ft | Bathrooms and damp areas |
A 12 ft × 12 ft room, 8 ft ceilings, walls and ceiling boarded, 4 × 8 ft sheets, 10% wastage:
Work out the area to board - the walls (room perimeter × ceiling height) plus the ceiling if you are boarding it - then divide by the area of one sheet and add wastage. A 12 × 12 ft room with 8 ft ceilings and the ceiling boarded is about 528 sq ft; with 4 × 8 ft sheets (32 sq ft each) and 10% wastage that is 19 sheets. Enter your room above for the exact count.
Lowe's stocks standard 1/2 inch drywall in 4 × 8 ft sheets (32 sq ft) and 4 × 12 ft sheets (48 sq ft), along with 5/8 inch fire-rated Type X board, 1/4 inch flexible board for curves, and moisture- and mold-resistant board for bathrooms. The calculator defaults to 4 × 8 ft; switch to 4 × 12 ft for long walls where the bigger sheets cut down on joints.
Use 1/2 inch board for most walls and ceilings. Step up to 5/8 inch Type X where code calls for a fire rating - garages, walls between a house and garage, and many ceilings - and because the thicker, stiffer board sags less overhead. The sheet area is the same (32 sq ft for a 4 × 8), so the calculator's sheet count holds either way; just buy the board the job requires.
Allow roughly 0.6 kg of joint compound per square metre of board for a taped three-coat finish - about one 4.5 gallon (61.7 lb) box of all-purpose mud per 475 sq ft of board - and one 250 or 500 ft roll of tape for a typical room. The calculator gives the compound and tape totals from your boarded area so you know how many boxes and rolls to put in the cart.
About 32 coarse-thread drywall screws fix a 4 × 8 ft sheet to wood studs at 16 inch centres - a screw roughly every 12 inches in the field and 8 inches around the edges, with ceilings fixed more densely. A 1 lb box holds around 175-225 screws, so a small room is usually a box or two. The calculator multiplies your sheet count by 32.
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