Plasterboard calculator: sheets, screws and tape
The calculator needs JavaScript. The worked example, formula and figures below show exactly how it works, so you can do the sum yourself. A guide, not advice. Check your supplier's or maker's figures before ordering.
Short answer
A 4 × 3 m room with 2.4 m walls has 33.6 m² of wall: 13 sheets of 2400 × 1200 mm board with our 10% waste allowance, or 18 sheets for walls and ceiling together. Openings reduce it. Screws, tape and filler come from your board maker's rates; for adhesive, use the dot and dab calculator.
Work out how many plasterboard sheets walls and ceilings need, and the screws, jointing tape, joint filler and bead to go with them. Enter your measurements below; every figure we start from is shown and you can change it.
Worked example
| You enter | Value |
|---|---|
| Walls and ceilings | Room: room walls 4 m × 3 m × 2.4 m, less 0.8 × 2 m, 1.2 × 1.1 m |
| Board size | 2400 × 1200 mm |
| Waste allowance | 10% |
Order: 12 boards
| Result | Value |
|---|---|
| Boards | 12 |
| Area (after openings) | 30.68 m² |
Show the working
- Area: Room 33.6 m² less 2.92 m² = 30.68 m²
- Boards: 30.68 × 1.1 (10% waste) ÷ (2,400 × 1,200 mm = 2.88 m²) = 11.72, rounded up to 12
How it works
- Boards = net area × (1 + waste) ÷ board area, rounded up
- Screws = boards × screws per board (maker's fixing guide)
- Tape (m) = boarded area (boards × board area) × tape per m²; rolls = tape ÷ roll length, rounded up
- Joint filler (kg) = boarded area × filler per m²; bags = filler ÷ bag size, rounded up
- Bead (m) = bead run × (1 + waste); lengths = bead ÷ length of one bead, rounded up
Screws, tape, filler and bead come from the maker's rates for the system you use, so enter them from the product or its estimating guide. We haven't sourced typical figures yet.
Fire-resistant and moisture-resistant boards are specified for some rooms: check the maker's guidance and building regulations.
Our default (adjustable)
These are typical planning figures and our own allowances, not facts about your product. Change any of them in the calculator to match your bag, pack or tin.
| Figure | Our default (adjustable) | Kind | Source |
|---|---|---|---|
| Waste allowance | 10 % | Our assumption Not yet checked against the source | Our choice: change it to suit your job Cuts and offcuts. |
| Screws per board | Enter from the bag, pack or tin | Typical value Not yet checked against the source | From your product Enter from the board maker's fixing guide. |
| Jointing tape per m² of board | Enter from the bag, pack or tin | Typical value Not yet checked against the source | From your product brief v2 §2 (plasterboard: jointing tape from maker rates, null until sourced). Metres of jointing tape per m² of board. Researcher to source from a board or jointing system maker's estimating guide. |
| Length of one roll of tape | Enter from the bag, pack or tin | Common UK size Not yet checked against the source | From your product brief v2 §2 (plasterboard). Length of one roll of jointing tape. Researcher to source from merchant listings; until then the user enters it from the roll. |
| Joint filler per m² of board | Enter from the bag, pack or tin | Typical value Not yet checked against the source | From your product brief v2 §2 (plasterboard: joint filler from maker rates, null until sourced). Kg of joint filler per m² of board. Researcher to source from a jointing compound maker's coverage figure. |
| Joint filler bag size | Enter from the bag, pack or tin | Common UK size Not yet checked against the source | From your product brief v2 §2 (plasterboard). Bag size of joint filler. Researcher to source from merchant listings; until then the user enters it from the bag. |
| Length of one bead | Enter from the bag, pack or tin | Common UK size Not yet checked against the source | From your product brief v2 §2 (plasterboard: bead). Length of one angle or stop bead. Researcher to source from merchant listings; until then the user enters it from the product. |
FAQs
How many plasterboard sheets do I need?
Add up the wall and ceiling areas, take off doors and windows, add a waste allowance for offcuts, then divide by the area of one board and round up. A 2400 × 1200 mm board covers 2.88 m². The calculator shows each step: the walls of a 4 × 3 m room at 2.4 m high, less a door and a window, come to 30.68 m², which is 12 boards with 10% waste.
How many sheets of plasterboard for a ceiling?
Measure the ceiling's length and width and add it as a ceiling area. A 4 × 3 m ceiling is 12 m², which is 5 sheets of 2400 × 1200 mm board with our 10% waste allowance.
What size are plasterboard sheets?
The common UK sizes are 2400 × 1200 mm, 2400 × 900 mm and 1800 × 900 mm, and the calculator offers all three. Narrower boards mean more sheets for the same wall: the 33.6 m² of wall above takes 18 sheets of 2400 × 900 mm instead of 13 of 2400 × 1200 mm. Check the size your merchant stocks.
Should I take doors and windows off the area?
Yes. Add each opening to the wall it's in and the calculator takes it off. The waste allowance covers the offcuts you get from cutting round openings and at corners; it's our assumption (10%), so change it if you work more or less carefully.
How many screws do I need per plasterboard sheet?
It depends on the board, its thickness and whether it's going on a wall or a ceiling, so we don't assume a figure. Enter the number from your board maker's fixing guide and the calculator multiplies it by the number of boards. Jointing tape and joint filler work the same way, from the maker's rates per square metre.
Should I screw plasterboard or use dot and dab?
On timber or metal studs and ceiling joists, boards are screwed. On a solid masonry wall they're often bonded with dabs of adhesive instead. If you're dot-and-dabbing, the dot and dab calculator works out the adhesive bags for the same area.
Guides
How many plasterboard sheets do I need?
Plasterboard sizes, walls vs ceilings, offcuts, fire and moisture-resistant boards, and when to hire a plasterer.