Drywall Calculator
Calculate how many drywall sheets and materials you need.Calculate how many drywall sheets and materials you need — including waste and openings.
You'll need
545.6sq ft
18 Sheets
What are the room dimensions?
Live diagram
You'll need
545.6sq ft
Recommended drywall area
Sheets: 18 of 4' × 8'
Getting your drywall order right
Deduct doors and windows from wall area, account for cutting waste, and check local code before choosing board type.
Working out drywall mud and tape
Joint compound — usually just called mud on site — is sold in buckets by weight. As a rule of thumb, allow roughly one 4.5-gallon bucket per 90 square feet of Sheetrock for a standard three-coat finish, plus about one 250 ft roll of paper tape per 135 square feet. This drywall mud calculator works both out automatically from your room dimensions, so you don’t have to estimate separately.
Tiling a bathroom or kitchen wall instead of finishing it? Use the tile calculator for backsplash and shower surrounds.
Related calculators
- concrete calculator — for basement and garage slabs under the walls.
- fence calculator — for exterior work on the same property.
FAQFrequently asked questions
For walls only at 8 ft height, that’s about 2×(12+12)×8 = 384 sq ft. With 10% waste and 4×8 sheets (32 sq ft each), that’s roughly 14 sheets — add the ceiling for a full room.
4×8 sheets are easiest to handle alone. 4×12 sheets mean fewer seams but need two people and more room to maneuver.
10% is standard. Rooms with many openings, angled walls, or complex cuts often need 15–20%.
Joint compound — commonly called mud — is estimated here at roughly one 4.5-gallon bucket per 90 sq ft of drywall. Actual usage varies by number of coats and finish level.
Sheetrock is a brand of drywall made by USG, used so widely in the US that the name is often used generically. The calculations are identical — sheet sizes, mud coverage and screw spacing don’t change between brands.
We estimate about one 250 ft roll per 135 sq ft of drywall — adjust based on how many seams your layout actually has.
1/2" is standard for most walls and ceilings. 5/8" (often fire-rated) is common for garages, shared walls, and some ceiling spans — check local code.
| Thickness | Typical use |
|---|---|
| 1/2 inch | Standard for most walls and ceilings |
| 5/8 inch | Fire-rated applications, garages, ceilings with wider joist spacing |
Bathrooms, laundry rooms and other humid spaces typically benefit from moisture-resistant board — it is not automatically required everywhere.
Many jurisdictions require fire-rated board on garage walls/ceilings shared with living space — check your local building code before ordering.