Drywall Calculator
Enter your dimensions for an instant answer — the exact quantity to buy (waste included), a material cost, and an estimated installed cost. Change any figure to update the result live.
| ITEM | QTY | PRICE RANGE |
|---|---|---|
| 4x8 sheets (32 ft²) | 28 | $308–$504 |
| Estimated material total | $308–$504 |
- Drywall screws: 896 screws (≈ 3 lb)
- Joint compound: 6.6 gallons
- Joint tape: 334 ft
- 19 × 4x12 sheets (48 ft²) — $304–$494
How much drywall do I need?
Add up the square footage of every wall and ceiling you are covering — for a full room, that is perimeter × wall height plus length × width for the ceiling. Enter the total and the calculator converts it to 4×8 sheets (32 sq ft each), shows the 4×12 alternative for long walls, and adds 10% for cuts and waste.
It also computes the finishing materials for the walls-and-ceiling job in one pass: drywall screws, joint compound (mud) and tape, so nothing is missing when you order.
Formula & methodology
sheets = (wall + ceiling ft² × 1.10) ÷ 32 ft² per 4×8 sheet, rounded up
Area plus a 10% waste allowance, divided by sheet coverage and rounded up to whole sheets. Companion quantities per 100 sq ft: about 0.75 gallons of joint compound and 38 feet of tape, with roughly one screw per square foot.
All constants are published on the material reference; the full model is on the methodology page.
800 sq ft of wall/ceiling: you need 25 4x8 sheets (32 ft²) (buy 28 with waste), about $308–$504 in materials. See how we calculate this →
Drywall cost
4×8 sheets run $11–$18 each nationally; hanging and finishing labor is the bigger cost driver and varies by state.
drywall cost by state →Frequently asked questions
How much drywall do I need?
Measure total wall and ceiling area in square feet — that single number is all the calculator needs. As a shortcut, a 12×12 room with 8-foot ceilings is about 384 sq ft of wall plus 144 sq ft of ceiling, or roughly 19 4×8 sheets with waste.
How many drywall sheets do I need?
Divide total wall and ceiling area by 32 (for 4×8 sheets) or 48 (for 4×12), then add ~10% for waste. The calculator also gives screws, mud and tape.
How much drywall mud do I need?
Plan on about 0.75 gallons of ready-mixed joint compound per 100 square feet of drywall, so an 800 sq ft job takes about 6 gallons. The calculator lists mud, tape and screws with every result.
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