# Drywall Sheet Count Calculator

> Count drywall or plasterboard sheets for a room’s walls and ceiling from its size, openings and sheet size (4×8, 4×12 ft or 1200 mm boards), with waste.

Category: Construction · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/drywall-sheet-count-calculator

Add the wall area (perimeter × height, less openings) and the ceiling, add a waste allowance, and divide by the area of one sheet.

Also called: Plasterboard calculator, Sheetrock calculator, Gypsum board calculator.

## Inputs
- Units (options: Metric, Imperial; default imperial)
- Room length (default 12)
- Room width (default 10)
- Wall height (default 8)
- Doors and windows (total area) (default 40; optional)
- Include the ceiling (options: Yes, No; default yes)
- Sheet size (options: 4 × 8 ft, 4 × 10 ft, 4 × 12 ft, 1200 × 2400 mm, 1200 × 2700 mm, 1200 × 3000 mm; default 4x8)
- Waste allowance (unit %; default 10; optional)

## Results
- Sheets to buy
- Sheets of area (no waste)
- Total area
- Total area
- Wall area
- Ceiling area

## Formula

```
Area = 2(L + W) × H − Openings (+ L × W);  Sheets = ⌈Area × (1 + Waste) ÷ Sheet area⌉
```

Where:
- L, W, H: room length, width and wall height
- Sheet area: e.g. 4 × 8 ft = 32 ft², 1.2 × 2.4 m = 2.88 m²

## Worked example
1. Walls = 2 × (12 + 10) × 8 = 352 ft² − 40 ft² openings = 312 ft².
2. Plus ceiling 12 × 10 = 120 ft² → 432 ft².
3. 432 × 1.10 ÷ 32 ft² = 14.85 → 15 sheets.

**Result:** A 12 × 10 ft room with 8 ft walls and its ceiling needs 15 sheets of 4 × 8 drywall with 10% waste.

## What the result means

Longer sheets mean fewer joints to tape; boards for ceilings and wet areas may be a different type. Buy screws, tape and compound by area too.

## Assumptions and limits
- One layer of board on each surface.
- Sloped ceilings, soffits and bulkheads need to be added separately.

## Questions

### Should I subtract doors and windows?

Subtract large openings, but many installers leave small windows in because the cut-outs are mostly waste anyway.

### Which size should I buy?

Choose a length that spans the wall height or ceiling width with fewest joints, provided you can carry it into the room.

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_Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials._

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/drywall-sheet-count-calculator