# Drywall Calculator

Area to sheets, plus screws, tape and mud.

- Page: https://jianzhujisuan.com/en/drywall-sheets
- Category: Finishes (https://jianzhujisuan.com/en/c/finishes)
- Chinese version: https://jianzhujisuan.com/zh/drywall-sheets.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Wall and ceiling area 800 ft², Sheet size 4 × 8 ft (32 ft²), Layers Single layer, Waste 10%): **Drywall sheets 28 sheets**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Wall and ceiling area | number | 800 | ft² |  |
| Sheet size | select | 4 × 8 ft (32 ft²) | — |  |
| Layers | select | Single layer | — |  |
| Waste | number | 10 | % |  |

## Formula

- **Sheets = area × layers × (1+waste) ÷ sheet area**: round up
- **Screws (lb) = sheets × 32 ÷ 320**: 32 per sheet, 320 per lb
- **Tape rolls = area ÷ 500**: a 500 ft roll does about 500 ft²
- **Mud (gal) = area ÷ 100 × 0.5**: three-coat finish

## Worked example

800 ft² single layer in 4x8 sheets with 10% waste: 880 ft², so 28 sheets, about 2.8 lb of screws, 2 rolls of tape and 4.4 gal of mud - one 4.5 gal bucket.

## Questions

### How should I measure the area?

Walls are perimeter times clear height, less openings (about 20 ft² for a door and 15 ft² for a window). Ceilings are length by width. Do not multiply floor area by a factor - ceiling heights and partition counts vary so much that the usual 2.5 to 3.5 range carries up to 30% error. Measure once and be done.

### 4x8 or 4x12 sheets?

4x12 cuts joints by a third, which saves mud and labour, and shows less on a big flat ceiling. But a 4x12 weighs about 65 lb (30 kg), which is not a one-person lift onto a ceiling, and it needs a longer trailer. Small rooms, stairwells and halls are easier and waste less in 4x8. The test: if a wall has 10 ft or more of continuous run, use 4x12.

### How many screws per sheet?

Code calls for 8 in at edges and joints and 12 in in the field, which works out at about 32 screws for a 4x8 sheet. Hand-driving wants each screw set about 1 mm into the paper without breaking it - driven too deep it loses holding power, which is the most common defect. A depth-stop collar on the driver cuts rework dramatically. Ceilings and second layers tighten to 7 in.

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