How to use the drywall calculator
- Enter the room length, width and wall height, and count the doors and windows.
- Choose the sheet size you plan to hang. Longer sheets mean fewer joints to tape on tall or long walls.
- Untick the ceiling if it is staying as it is.
- Open More options to change door and window sizes, the compound coverage, the bucket size and the tape roll length.
- Add prices per sheet, bucket and roll for a cost, then copy or print the shopping list.
How the estimate is worked out
Sheets = area × (1 + waste %) ÷ sheet area, rounded up
Screws ≈ 1 per sq ft of board hung (about 11 per m²)
Joint compound = area ÷ coverage; tape ≈ 0.37 ft per sq ft (about 1.2 m per m²)
The screw, compound and tape figures are planning rules of thumb, not manufacturer specifications. Real use depends on stud spacing, how many joints and corners the room has and how heavy-handed the finisher is, so they are shown as editable assumptions.
Worked example
A 12 × 10 ft room with 8 ft walls, one door and two windows, boarding the walls and the ceiling with 4 × 8 ft sheets and 10% extra:
- Walls: 2 × (12 + 10) × 8 = 352 sq ft, minus 51 sq ft of openings, plus a 120 sq ft ceiling = 421 sq ft.
- Sheets: 421 × 1.10 ÷ 32 = 14.47, rounded up to 15 × 4 × 8 ft.
- Screws at about one per square foot of board: 480 screws.
- Joint compound at 100 sq ft per gallon: 4.2 gal (1 × 4.5 gal bucket); tape at 0.37 ft per sq ft: 156 ft (1 × 500 ft roll).
- With boards at $16, a $20 bucket and a $6 roll of tape, the total is $266.00.
Tips and common mistakes
- Hang the ceiling first. Wall sheets then hold up the ceiling edges, and the joint at the top of the wall is easier to finish.
- Stagger the joints. Avoid four corners meeting at one point, and keep joints off the edges of door and window openings where cracks start.
- Use the right board. Moisture-resistant board belongs in bathrooms, and tiled shower areas need cement board or a proper backer and waterproofing. Fire-rated board may be required by code next to garages and between homes.
- Check what is behind the wall. Have a licensed electrician finish any wiring and inspections before boarding, because cutting open new drywall later costs far more than waiting.
US, UK and Canada differences
In the US and Canada, walls are usually hung with 1/2 in drywall on 16 in stud centres, with 5/8 in board on ceilings or wherever fire-rated board is required, and sheets come 4 ft wide in 8, 10 and 12 ft lengths. In the UK the same material is called plasterboard; the standard board is 1200 × 2400 mm, usually 12.5 mm thick, and many walls get a thin plaster skim over the whole surface instead of taped joints only. Joint compound is sold ready-mixed in buckets in North America, while UK jointing compound and filler are often sold as powder by the bag.
Metric units and other countries
Metric mode offers 1200 mm wide boards in 2400, 2700 and 3000 mm lengths and shows compound in litres. Many markets outside Europe sell 1220 × 2440 mm boards, which is simply the metric size of a 4 × 8 ft sheet; the 1200 × 2400 mm option gives a near-identical count for them. Gypsum board is widely used for false ceilings in Pakistan, India and the Gulf, and the ceiling-only area can be worked out by setting the wall height to a very small number and keeping the ceiling ticked.