How much plasterboard do I need?
Enter your room's length, width and wall height, choose a sheet size and tick the ceiling if you're boarding it — you'll get the number of plasterboard sheets to buy, with a screw estimate, instantly.
About 512 screws (rule of thumb ≈ 1 per ft²), walls + ceiling. The 10% waste allowance and the openings you didn't deduct cover offcuts.
Sheets = area to cover ÷ sheet area, rounded up, plus a waste allowance. Doors and windows are not subtracted — those offcuts become your small patches. Screw and compound amounts are planning rules of thumb, not code requirements.
Common questions
- How much plasterboard do I need?
- Work out the area to cover, then divide by the area of one sheet and round up. For a rectangular room the wall area is 2 × (length + width) × height; add length × width again if you are boarding the ceiling. A 12 ft × 12 ft room with 8 ft walls and the ceiling is 528 ft² of surface, which is 19 standard 4 × 8 ft sheets once you add a 10% waste allowance.
- How many sheets of plasterboard do I need for a room?
- Add up every wall (2 × (length + width) × height) plus the ceiling if you are covering it, divide by the sheet area — 32 ft² for a 4 × 8, 2.88 m² for a 1200 × 2400 mm board — and round up. The calculator above does it for you and adds your waste allowance; openings are left in, so the offcuts become your patches.
- What size are plasterboard sheets?
- In the US and Canada the standard sheet is 4 ft × 8 ft (32 ft²), with 4 × 10 and 4 × 12 used for taller walls and ceilings to cut down on joints. In the UK, Australia and New Zealand boards are 1200 mm wide and usually 2400, 2700 or 3000 mm long. Pick the size that matches your wall heights to minimise joints.
- Do you subtract doors and windows when estimating plasterboard?
- For small openings most estimators leave them in: the cut-out pieces become patches and small fills, and not deducting them gives a safe margin. Deduct only large openings — a wide patio door or a picture window — and keep a waste allowance of about 10% for offcuts and breakage either way.
- How many screws do I need per sheet?
- A common rule of thumb is roughly one screw per square foot, about 32 screws for a 4 × 8 sheet on walls and a few more on ceilings. Exact spacing depends on your stud or joist layout and local practice (often 12 in on ceilings, 16 in on walls), so treat the screw figure as a planning estimate, not a code requirement.
- How much joint compound and tape will I use?
- A handy planning rule is about one 4.5-gallon bucket of all-purpose joint compound and one 500 ft roll of paper tape per roughly 500 ft² of plasterboard — call it one bucket and one roll per average room, then scale up for bigger jobs. The exact amount depends on how many coats you apply and your finish level, so buy a little extra rather than running short mid-coat.
Want the full walk-through? Read the plasterboard guide →
Reference & education only. Not professional, engineering, or code-compliance advice. Estimates are based on published model codes; local amendments and your Authority Having Jurisdiction (AHJ) govern. Always verify against the current adopted code and a licensed professional before doing work.
Last reviewed 2026-06.