Drywall Calculator
Enter a room's length, width and wall height to get the drywall sheets for walls, ceiling or both, then the joint compound, tape and screws for the same board, rounded up once at each thing you buy. The sheets are the larger of the area count and the cut-layout count, and both are shown.
Estimates for planning, not professional advice. Read the full notice.
Example: a bedroom, walls and ceiling
22 4 × 8 ft sheets
- Walls and ceiling together 584 ft²
- Sheets by area, with the waste, before rounding 20.08 sheets
- Sheets by area, rounded up 21 sheets
- Sheets by layout, cutting each wall and the ceiling 22 sheets
- Sheets by area with the openings taken off 19 sheets
Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.
Your project
Enter a size to see your total.
Each product is rounded up once for the whole project, so the total can be less than the items bought alone added together. A line counted from a cut layout (sheets, boards or tiles laid out piece by piece) is counted for each item and added.
Shopping list
| Item | Size | Buy |
|---|---|---|
| Drywall sheets | 4 × 8 ft sheet | 22 |
| Joint compound pails | 4.5 gal can | 2 |
| Joint tape rolls | 250 ft roll | 1 |
| Drywall screws | screws | 730 |
Save on this device
Saved projects
No saved projects yet.
Worked example: a bedroom, walls and ceiling
Show the working
- Walls: the perimeter times the wall height 52 ft × 8 ft = 416 ft²
- Ceiling: length times width 14 ft × 12 ft = 168 ft²
- Add the waste allowance, once 584 ft² + 10 % waste = 642.4 ft²
- Divide by the area of one sheet 642.4 ft² ÷ 32 ft² = 20.08 sheets
- Round up once, to whole sheets 20.08 sheets = 21 sheets
- Count the layout too and order the larger of the two, so a cut layout is never short 22 sheets = 22 sheets
Assumptions
The figures behind the example. Sourced figures link to their source below; a default is a starting value to check against your label or supplier.
| Assumption | Value | Details and changes |
|---|---|---|
| Waste allowance | 10% | |
| Default An example allowance for cuts and breakage, added once. Change it for your own job. | ||
| Sheet size | No default | |
| Default Choose the size your supplier sells from the list above the result. Check your label or supplier. | ||
| Joint compound per 1,000 ft² of board | 10 gal | |
| Default An example to start from, not a maker figure. Check your label or supplier. It is a field above the result. | ||
| Joint tape per 1,000 ft² of board | 370 ft | |
| Default An example to start from, not a maker figure. Check your label or supplier. It is a field above the result. | ||
| Board area per screw | 0.8 ft² | |
| Default An example to start from, not a maker figure. Check your label or supplier. It is a field above the result. | ||
| Pail size | No default | |
| Default Choose the pail on your label from the list above the result. Check your label or supplier. | ||
| Tape roll length | No default | |
| Default Choose the roll on your label from the list above the result. Check your label or supplier. | ||
Feet and inches, like 12' 6"
Sheets by sheet size
Sheets for the example room's walls and ceiling at each sheet size, with the waste allowance, openings not taken off and taken off
| Sheet | Openings not taken off | Openings taken off |
|---|---|---|
| 4 × 8 ft | 21 | 19 |
| 4 × 10 ft | 17 | 15 |
| 4 × 12 ft | 14 | 13 |
| 54 in × 12 ft | 12 | 11 |
Each row is the area method on the worked example's room at the waste allowance in the assumptions. A longer sheet covers more area, so the count falls. The calculator's order is the larger of this area count and the layout count, which cuts each wall and the ceiling row by row and can be higher.
Questions
How many sheets do I need for the walls and the ceiling?
Enter the room's length, width and wall height and choose Walls and ceiling. The calculator adds the four walls and the ceiling, adds your waste allowance once, divides by the area of one sheet and rounds up once, then counts the cut layout and orders the larger of the two counts. Choose Walls or Ceiling to count one surface alone.
Does a 4 × 12 ft sheet change the count?
Yes, a longer sheet covers more area, so the count usually falls. Change the sheet size above and the sheets, and the finishing that follows the board area, update together. The worked example shows the 4 × 12 ft count beside the 4 × 8 ft one.
Do the doors and windows come off the count?
The calculator starts with the walls counted gross, with openings not taken off, and shows the count with the openings taken off beside it. Enter the area of your openings and switch Openings to Taken off to count them out.
Where do the compound, tape and screw amounts come from?
From three rates in the fields above, each started at an example, not a maker figure. Replace them with the rates on your own labels and the pails, rolls and screws follow the board area.