Drywall Calculator
Enter your room dimensions and sheet size. We'll tell you exactly how many sheets to pick up.
Advanced options
- Wall area
- 0 sq ft
- Ceiling area
- 0 sq ft
- Total area
- 0 sq ft
- With waste factor
- 0 sq ft
- Estimated cost
- —
How the drywall calculator works
We calculate the wall area (2 × (length + width) × height), subtract 20 sq ft per door and 15 sq ft per window, and add the ceiling if you're sheeting it. Then we apply a 15% waste factor — higher than paint because drywall has real cutoff waste — and divide by your sheet's square footage, rounding up.
4×8 vs 4×12 — when to pick each
4×8 (32 sq ft) is the default: easy to carry up stairs, fits a pickup truck bed, standard for residential. 4×12 (48 sq ft) reduces the number of horizontal seams on long walls — less mudding and better aesthetics — but requires two people to hang and doesn't fit in tight spaces. If the longest wall is over 12 feet, 4×12 is usually worth the hassle.
Why the waste factor is 15% for drywall
Every door and window cutout produces a piece that's usually too small to reuse. Corner breaks happen. Damaged sheets happen. 15% is realistic for a homeowner; pros with good cutting technique can run 10%. Complex layouts with lots of closets or odd corners can push to 20%.
Don't forget
- Screws: roughly 32 drywall screws per sheet on walls, 50 per sheet on ceilings.
- Joint compound (mud): a 4.5-gallon pail covers ~300–400 sq ft for taping + 2 coats.
- Tape: paper tape runs ~50 ft per sheet.
- Corner bead: one 8-foot piece per outside corner.