Drywall Calculator
Sheets, screws, and cost for walls and ceilings from area.
What it does
Drywall math is area divided by sheet size with a cuts allowance, plus fasteners by the sheet. One 4x8 sheet covers 32 square feet, and ceilings plus tall walls stack sheets in courses that the waste share absorbs.
The tool above takes area in feet or meters with the matching sheet sizes. It returns sheet count, screw count at 32 per sheet, and cost at your sheet price.
Orientation saves cuts. Hanging long sheets horizontally halves butt joints on eight foot walls, and ceilings want the longest sheets that fit through the door.
Thickness follows framing: half inch for standard walls, five eighths for ceilings and fire ratings, quarter inch skins over old surfaces. Sheet count ignores thickness, which pricing does not.
How to use
- Switch the unit system first: imperial for feet, metric for meters.
- Measure wall and ceiling area, subtracting big openings.
- Pick the sheet size you can carry inside.
- Buy sheets plus one spare for breakage.
Formula
- 32 ft2
- One 4x8 US sheet coverage.
- 3.0 m2
- One 120x250 cm EU sheet coverage.
- x 32
- Screws per sheet on 16 inch framing.
Openings under doors and windows rarely justify subtracting since offcuts fill odd bays. Subtract only garage doors and larger holes.
Worked example
Example: 512 ft2, 10% waste, $15 sheets
Walls and ceiling total 512 ft2.
- With waste: 512 x 1.10 = 563.2 ft2.
- Sheets: 563.2 / 32 = 17.6, round up to 18.
- Screws: 18 x 32 = 576.
- Cost: 18 x $15 = $270.00 before tape and mud.
Reference table
| Wall area | Sheets | Screws |
|---|---|---|
| 256 ft2 | 9 | 288 |
| 384 ft2 | 14 | 448 |
| 512 ft2 | 18 | 576 |
| 768 ft2 | 27 | 864 |
Limits
- Flat area math. Angles and curves waste more.
- Thickness choice sits outside the count.
- Framing at 24 inches wants different screw spacing.
- Delivery and hanging labor excluded.
Common mistakes
- Buying exact sheets with no breakage spare.
- Measuring the floor instead of walls plus ceiling.
- Hanging short sheets vertically on tall walls.
- Skipping ceiling sheets from the count.
- Underbuying screws and stalling mid wall.
Try it yourself
Quick checks. Answers sit tucked under each question.
300 ft2, no waste. Sheets?
300 / 32 = 9.375, so 10 sheets.
47.6 m2 metric, 10% waste, 3.0 m2 sheets?
52.36 / 3.0 = 17.45, so 18 sheets.
Questions
How many screws per drywall sheet?
About 32 on 16 inch framing: four per stud across eight studs.
Horizontal or vertical hanging?
Horizontal on 8 ft walls halves butt joints. Vertical suits tall commercial walls.
What thickness should I buy?
Half inch for walls, five eighths for ceilings and garages, quarter inch for skins.
How much joint compound per sheet?
Roughly one gallon per four to five sheets for standard finishing.
Can one person hang drywall?
With a lift, yes. Full sheets weigh 50 plus pounds and break backs.
Do ceilings need different sheets?
Five eighths resists sag between joists. Half inch sags on wide spans.