Drywall Sheet Calculator
Work out how many drywall sheets any area needs — from the total area and the sheet size, with a cutting allowance and the offcut area shown.
Sometimes you already know the area — from a plan, a supplier's quote, or the wall area calculator. This page turns that one number into a sheet count, with wastage and the spare board shown.
For a room you have not measured yet, use the drywall calculator, which works the area out from the room size.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.
How to use this calculator
- Enter the total drywall area (walls + ceiling).
- Enter the sheet size.
- Set wastage at 10%.
- Add a price per sheet for a cost estimate.
Worked example
| Area | 612 ft² |
|---|---|
| Sheet | 4 × 8 ft = 32 ft² per sheet |
| Sheets | ⌈(612 × 1.10) ÷ 32⌉ = ⌈21.04⌉ = 22 sheets |
| Offcut area | 22 × 32 − 612 = 92 ft² of spare board |
Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.
Frequently asked questions
What is the difference between this and the drywall calculator?
This page takes a total area you already know — from a plan, a quote, or the wall area calculator — and turns it into sheets. The drywall calculator works the area out from the room size and adds screws.
How much drywall wastage should I allow?
10% is standard. Offcuts from one wall often fit elsewhere, but sheets get damaged in handling and some cuts are unusable. Large straight walls can use 5%; rooms with many corners need 15%.
What do I do with the offcuts?
Keep the larger ones: they patch holes, fill small areas, and cover future repairs. The calculator shows the offcut area so you know how much spare board you will have.
Which drywall thickness do I need?
1/2 in (12.5 mm) is standard for walls; 5/8 in (15 mm) for ceilings and fire-rated walls; 1/4 in (6 mm) for curves. Thickness does not change the sheet count — only the weight and the price.
Related calculators
Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.