Drywall Calculator

Enter the room dimensions to get total drywall area for the four walls, with an optional ceiling, and the number of sheets to buy. A standard 4×8 sheet covers 32 sq ft and a 4×12 sheet covers 48 sq ft; sheet counts are rounded UP to whole sheets.

Pros often prefer 4×12 sheets on long walls because fewer joints means less taping, but they are heavier and harder to move through a finished house. This estimate covers full sheets only — order one or two extra for damage and cutting mistakes.

The formula

Wall area = 2(L + W) × H; Total = Walls + Ceiling (optional); Sheets = ceil(Total ÷ sheet area)

Worked example

A 12 × 10 ft room with 8 ft ceilings needs 352 sq ft of wall board plus a 120 sq ft ceiling — 472 sq ft total, which is 15 sheets of 4×8.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

Should I subtract doors and windows?

Estimators usually do not for typical rooms: the offcuts around openings are largely lost to cutting, and the small surplus covers damaged corners. For a wall that is mostly glass, subtract the openings manually from the total area.

4×8 or 4×12 sheets — which is better?

4×12 sheets create fewer butt joints on long walls and ceilings, so finishing is faster, but each sheet weighs about 50% more. Most DIYers find 4×8 sheets much easier to handle.

What thickness of drywall do I need?

1/2 inch is standard for walls, 5/8 inch (often fire-rated Type X) for garages and some ceilings, and 1/4 inch for going over existing surfaces or curved work. Thickness does not change the sheet count.

Category: Construction & Home calculators