Drywall Calculator — Free Online Tool
Drywall math is unforgiving — sheets are heavy, bulky, and stores charge per delivery. This drywall calculator converts your wall and ceiling area into sheet counts plus the mud to finish them.
What is the Drywall Calculator?
A standard 4×8 sheet covers 32 square feet. Pros hang sheets horizontally on walls to reduce seams, and use 5/8-inch fire-rated board on ceilings and garages where code requires it. The 10% waste factor covers cutouts for outlets, windows, and the inevitable broken corner.
Don't forget the finishing materials: roughly one 5-gallon bucket of joint compound per 400 square feet, a roll of tape, and screws (about one pound per sheet). This drywall calculator gives you sheets and compound buckets — add corner bead for every outside corner. And hanging is a two-person job: a full sheet weighs 50+ pounds.
How to use this calculator
- Measure all walls and ceilings (length × height) and total the area.
- Enter the area and click Calculate Drywall.
- Add corner bead for every outside corner.
- Plan delivery — sheets don't fit in most cars.
Formula
Frequently asked questions
1/2-inch vs 5/8-inch drywall — which do I need?
5/8-inch for ceilings and where fire code requires it (garages); 1/2-inch for standard walls. This drywall calculator's sheet count works for either.
How much joint compound per sheet?
Roughly one gallon per sheet across all coats — about one 5-gallon bucket per 400 sq ft.
Should drywall hang horizontally or vertically?
Horizontally on walls: fewer seams, and the tapered edges land at a convenient finishing height.
How many screws per sheet?
About 28–32 screws per 4×8 sheet — every 12 inches on ceilings, 16 inches on walls.