Drywall Calculator

Work out how many sheets of drywall you need for a room's walls and ceiling, after taking out doors and windows and adding extra for cuts, and compare 4 × 8, 4 × 10 and 4 × 12 ft sheets. Your inputs stay in your browser.

Your room and drywall

The room

Floor to ceiling; 8 feet is common.

Doors and windows

A 3 × 7 ft door is 21 sq ft.

Width × height in feet; 3 × 4 ft is 12 sq ft.

The drywall

Sheet size

About 10% for a typical room; more for many corners or angles.

19 sheets of 4 × 8 ft drywall for 539.0 sq ft. See full results

Example: a 12 × 14 ft room with 8 ft walls and the ceiling, 1 door and 2 windows, 10% extra, in 4 × 8 ft sheets. Enter your numbers to update.

Your drywall estimate

Sheets to buy
19
4 × 8 ft sheets, 32 sq ft each
Area to cover
539.0 sq ft
592.9 sq ft with 10% extra

How the area adds up

SurfaceArea
Walls (12 + 14) × 2 × 8 ft 416.0 sq ft
Less doors and windows −45.0 sq ft
Ceiling 168.0 sq ft
Total to cover 539.0 sq ft

Sheets needed by size

Sheet sizeSheets
4 × 8 ft (32 sq ft) 19
4 × 10 ft (40 sq ft) 15
4 × 12 ft (48 sq ft) 13

Add a price per sheet to estimate the cost.

How to calculate drywall

  1. Walls: add the room's length and width, double it for the perimeter and multiply by the wall height: (12 + 14) × 2 × 8 = 416 square feet.
  2. Doors and windows: subtract their area. 1 door of 21 sq ft and 2 windows of 12 sq ft take off 45, leaving 371.
  3. Ceiling: length × width = 168 square feet, for 539 in total.
  4. Waste: add 10% for cuts and mistakes: 592.9 square feet.
  5. Sheets: divide by the area of one sheet and round up. A 4 × 8 ft sheet is 32 square feet, so 592.9 ÷ 32 → 19 sheets. Measure in inches? Divide square inches by 144 for square feet (NIST: tables of units of measurement).

Walls only, the same room needs 13 sheets of 4 × 8 ft.

4 × 8, 4 × 10 or 4 × 12 sheets?

For the example room, 4 × 8 ft sheets mean 19 sheets, 4 × 10 ft sheets 15 and 4 × 12 ft sheets 13. Longer sheets cover more wall with fewer joints to tape and finish, but they are heavier and harder to carry through doors and up stairs, and a sheet that is longer than a wall is wasted in the offcut. Many people hang 4 × 8 sheets by themselves and use longer sheets with a helper.

Thickness does not change the count. Half-inch drywall is common on walls; ceilings and some walls, such as between a garage and the house, may call for 5/8-inch or fire-rated board under your local building code.

What this calculator does not include

  • Joint compound, tape, screws and corner bead, which depend on the layout and finish level.
  • Rooms that are not rectangular, sloped or vaulted ceilings, and walls of different heights. Work those out wall by wall.
  • Installation labor.

Results are estimates for planning a purchase. A contractor's takeoff for your plans may differ.

Methodology and testing

Automated tests compare wall, ceiling and opening areas and sheet counts for every size with an independent calculation, and check that an area that is an exact number of sheets is not rounded up an extra sheet. How we build and test calculators.

Sources

  • Flooring Calculator

    Square footage for several rooms, waste by layout, boxes from carton coverage, leftover and cost.

  • Roofing Calculator

    Roof area from footprint and pitch, roofing squares, waste, and shingle bundles with cost.

  • Square Footage Calculator

    Square feet of a rectangle, circle, triangle or trapezoid in any unit, with square yards, square meters, acres and cost.