# Drywall Calculator

> Calculate drywall step by step: Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.

Page: https://freecalculator.tech/tools/drywall-calculator
Last reviewed: 2026-11-03

## Formula

Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.

- One layer, one side of each wall.
- Openings are deducted.
- Sheet size is entered.
- Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉.
- Inputs used: Room perimeter, Wall height, Ceiling area (0 if none), Openings area, Sheet width, Sheet length, Waste allowance.

## Inputs

- Room perimeter
- Wall height
- Ceiling area (0 if none)
- Openings area
- Sheet width
- Sheet length
- Waste allowance

## Worked example: 4 × 4 m room with ceiling

1200 × 2400 mm sheets, 10% waste.
1. Area = 38.4 + 15 − 3 = 50.4 m².
2. With waste = 55.44 m².
3. ÷ 2.88 = 19.25 → 20 sheets.

## Common questions

### Should I deduct small openings?

Many estimators don't deduct small openings because offcuts are rarely reusable. Enter 0 to be conservative.

### What about both sides of a partition?

Double the wall area, or enter twice the perimeter.

### Are screws and tape included?

No, only board sheets.

### How much waste should I allow?

Around 10% is a common starting point for simple rooms; use 12–15% for many corners, openings or cut-heavy layouts. Set it from your own jobs.

### How do I use the Drywall Calculator?

Enter the required values for Room perimeter, Wall height, Ceiling area (0 if none), Openings area, Sheet width, and the other fields shown. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

### What formula does the Drywall Calculator use?

Sheets = ⌈(perimeter × height + ceiling − openings) × (1 + waste) ÷ sheet area⌉. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.

## Limitations and assumptions

- Single layer.
- No accessories.
- Simple rectangular rooms.
- Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
- The result depends on the values you enter for this drywall calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Sources

- OpenStax (Rice University) — https://openstax.org/details/books/prealgebra-2e

## Cite this page

- APA: Free Calculator. (2026, November 3). Drywall Calculator. https://freecalculator.tech/tools/drywall-calculator
- MLA: "Drywall Calculator." Free Calculator, 3 Nov. 2026, https://freecalculator.tech/tools/drywall-calculator.
- Link: Drywall Calculator — Free Calculator, https://freecalculator.tech/tools/drywall-calculator