What is Drywall Calculator?

Drywall Calculator estimates how many drywall sheets you need for a room or wall project. Enter room dimensions and door/window openings, and get an accurate material count with waste factor included.

Punch in wall height and total length for each room, then deduct doors and windows. Add a second or third room and the tool sums sheets across the whole project. Switch on custom dimensions for non-standard openings, tick the ceiling box, or add a triangle section for vaulted or A-frame rooms. The calculator handles feet, meters, and centimeters, supports four sheet sizes (4 by 8 through 4 by 12), half-inch and five-eighths board thickness, 16- or 24-inch stud spacing, a waste factor between 5 and 20 percent, and an optional price per sheet for a cost estimate.

How to use

1. Enter the wall height and total wall length for each room. Tap Add Room to include a second or third room and the sheet total rolls up across the whole project.
2. Count the doors and windows in each room. Tick the custom dimensions box if any openings are non-standard, and add a ceiling or sloped section toggle for vaulted rooms.
3. Pick a sheet size (4 by 8 through 4 by 12), choose the board thickness and stud spacing, set the waste factor, and add a price per sheet for a cost estimate. You get the total sheet count plus a materials checklist of screws, tape, and joint compound.

When to use

• Planning a basement build-out and need to budget materials before a Home Depot run.
• Pricing a renovation quote and want a quick sheet count to attach to the estimate.
• Replacing water-damaged drywall in a single room and don't want to over-buy.

Result

A homeowner calculates drywall for a 12×14 ft room with 8 ft ceilings, 2 doors, and 1 window — needing 14 sheets of 4×8 drywall with 10% waste.

FAQ

How does the calculator handle ceilings and vaulted rooms?

Tick the ceiling box on any room and enter its length and width. For vaulted or A-frame rooms, also tick the sloped section toggle and enter the triangle base and height — the tool adds half base times height to your wall total.

Why does it default to 10% waste?

Ten percent is the industry rule of thumb for a hanger working alone in a square room. Bump to 15% for rooms with lots of corners, multiple windows, or vaulted ceilings where you'll cut more odd pieces.

What dimensions should I use for doors and windows?

By default the tool assumes a 3 by 7 ft door (21 sq ft) and a 3 by 5 ft window (15 sq ft). Tick the custom dimensions box on any room to enter exact widths and heights for non-standard openings — useful for sliding glass doors, French doors, or large picture windows.

Which sheet size should I pick?

4 by 12 sheets mean fewer seams to mud and tape, which speeds up finishing on long walls. Pick 4 by 8 if you're working alone or need to fit sheets through a narrow staircase — they weigh about 50 lb versus 75 lb. 4 by 9 and 4 by 10 sit between the two and pair well with 9- or 10-foot ceilings.

What screws, tape, and compound will I need?

The materials checklist estimates all three. Screws are counted by the piece and scale with stud spacing — roughly 32 per 4×8 sheet on 16-inch centers, 24 on 24-inch centers — and also shown by weight (about one pound per 100 square feet). Plan on one gallon of joint compound per 100 square feet and a 250 ft roll of paper tape per 12 sheets.

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