Contractor & construction
Drywall Calculator
Works drywall quantities, where the sheets are the smallest part of the order.
Result
Openings are not deducted, which is deliberate. The offcuts around a door or window are rarely reusable, so counting the full area is closer to what you actually buy.
Get a Free Business AuditHow the calculation works
Wall and ceiling area divided by the sheet area gives a sheet count, rounded up with a waste allowance, plus joint compound, tape, screws and corner bead. The ancillary materials are a substantial share of the order and are the items most often forgotten.
What moves the number
- Area including ceilings, less large openings.
- Sheet size chosen, which affects joint count.
- Waste from cuts around openings and in cut-up spaces.
- Compound, tape, screws and bead quantities.
Where this one goes wrong
Larger sheets produce fewer joints and less finishing work, which is why they are worth the handling difficulty where access allows, and joints are where the labour actually is rather than in hanging the board. Plan the layout to minimise them. Compound is the quantity most often underestimated, since the finishing coats consume considerably more than the taping coat and a job that runs out mid-finish stalls awkwardly.
Before you quote
- Choose sheet size to minimise joints where access allows.
- Order compound generously, since finishing consumes most of it.
- Include tape, screws and corner bead in the takeoff.
Questions
About this calculator
What sheet size should I use?
The largest the access allows, since larger sheets produce fewer joints and joints are where the labour is. The handling difficulty is usually worth it, and planning the layout to minimise joints matters more than the sheet count.
How much joint compound is needed?
More than people expect, because the finishing coats consume considerably more than the taping coat. Running out mid-finish stalls the job awkwardly, and compound keeps, which makes over-ordering the cheaper error.
Should openings be deducted?
Large ones yes, small ones generally not, because the cuts around a window or door produce waste that roughly offsets the area removed. Deducting every small opening tends to leave the order short.
The formula
sheets = (wall area × waste factor) ÷ sheet area
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How to use this calculator
- Total wall length (ft) (ft). Enter your own figure; the page starts at 48 ft.
- Wall height (ft) (ft). Enter your own figure; the page starts at 9 ft.
- Sheet size (sq ft) (sq ft). Enter your own figure; the page starts at 32 sq ft.
- Waste allowance (%). Offcuts around openings and corners.
- Cost per sheet ($). Enter your own figure; the page starts at $16.
The result updates as you type, so you can try a figure, see what it does to sheets needed, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Total wall length (ft) | 48 ft |
| Wall height (ft) | 9 ft |
| Sheet size (sq ft) | 32 sq ft |
| Waste allowance | 12% |
| Cost per sheet | $16 |
What comes out
| Result | Value |
|---|---|
| Sheets needed main result | 16 |
| Area | 432.0 |
| Area including waste | 483.8 |
| Estimated material cost | $256 |
| Joint compound (gallons) | 4.8 |
| Screws (approx.) | 533 |
For 432.0 sq ft plus 12% waste you need 16 sheets, costing about $256.
How sensitive the answer is
Holding everything else steady and changing only cost per sheet, this is what happens to sheets needed. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Cost per sheet ($) | Sheets needed |
|---|---|
| $8 | 16 |
| $12 | 16 |
| $16 example above | 16 |
| $24 | 16 |
| $32 | 16 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Total wall length (ft) (ft)
- Measured in ft, starting at 48 ft.
- Wall height (ft) (ft)
- Measured in ft, starting at 9 ft.
- Sheet size (sq ft) (sq ft)
- Measured in sq ft, starting at 32 sq ft.
- Waste allowance (%)
- Offcuts around openings and corners.
- Cost per sheet ($)
- A money amount, starting at $16.
What the results tell you
| Result | What it is |
|---|---|
| Sheets needed | The headline result. A number. |
| Area | A decimal figure. |
| Area including waste | A decimal figure. |
| Estimated material cost | A money figure. |
| Joint compound (gallons) | A decimal figure. |
| Screws (approx.) | A number. |
Overhead is where these go wrong
Pricing and margin figures are only as good as the cost you put in. If your cost covers parts and wages but not the van, the insurance, the phone and the unbilled hours, the markup is paying for those before it becomes profit, and the margin you think you are making is not the one you are making.
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