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Drywall Calculator

Estimate drywall sheet quantities from net wall and ceiling area.

Your numbers

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Updates as you type
Sheets to buy
13sheets

Calculated from your inputs · rounded for display

Net area360ft²
Area with allowance396ft²
Area per sheet32ft²
Material cost$195.00

Area-based material estimate; layout, cuts and openings can change quantities. Excludes labor, fasteners, adhesives and delivery.

Your calculation, step by step

No black boxes
  1. Net area = 400 − 40 = 360.
  2. With 10% allowance: 396 ft².
  3. Coverage per sheet = 32.
  4. Divide adjusted area by coverage, then round up to whole sheets: 13.

What if things were different?

Save up to three scenarios, then change your inputs to compare the possibilities.

How to use this calculator

  1. Enter your own values in the labeled fields. Check the units and assumptions before comparing results. Only the fields needed for your selected calculation mode are shown.
  2. Your answer updates automatically. Review the calculation steps to see exactly how it was calculated.
  3. Copy, share, save, or download your result. Saved inputs stay on this device.

How the calculation works

Sheets = ceil[(total area − openings) × (1 + waste/100) / sheet area]

Use the same system for total area and sheet dimensions. Subtract only openings that actually reduce your material requirement; small cutouts may not save sheets. This area method estimates quantity without optimizing seam placement, orientation or offcuts. Fasteners, tape, joint compound and labor are separate.

A worked example

400 ft² minus 40 ft² of openings leaves 360 ft². With 10% allowance, 396 ÷ 32 = 12.375: buy 13 sheets of 4 by 8 ft.

Reading your result

Use the main result together with its units and supporting figures. Display values are rounded; calculations keep their underlying precision. A change in inputs or assumptions can change the answer. Compare the step-by-step working with your intended use before relying on an estimate.

Frequently asked questions

Does it optimize a cutting plan?

No. It uses net area and a user-entered allowance.

Are ceilings included?

Yes, if their area is included in the total.

Sources & methodology

This calculator uses the mathematical identity and assumptions stated above. No current rates, prices, or external data are loaded. Conversion tools use international unit definitions.

Formula review: October 24, 2026. Read our methodology.