Estimate drywall sheets, joint compound, tape, screws, and corner bead for rooms or single walls.
| Material | Amount | Buy |
|---|---|---|
| Joint compound | 3.0 gal | 1 × 3.5 gal pail |
| Joint tape | 540 ft | 3 × 250 ft rolls |
| Drywall screws (1¼″) | 5.4 lb | 2 × 5 lb boxes |
| Corner bead | 0 ft | — |
Advanced · custom opening sizes · cost
Reverse: I have N sheets — what area do they cover?
Enter the sheet count and size you already have, then see the gross drywall area you can cover at your chosen waste margin.
How the math works
Drywall is square-footage work with a deduction step. The calculator does five things in order:
- Wall area:
2 × (length + width) × ceiling_height - Ceiling area:
length × widthif you tick the ceiling box - Subtract openings: doors at 21 sf each (3′ × 7′), windows at 12 sf each (3′ × 4′) — overrides live in the advanced panel
- Add a waste margin (10% residential default) — covers cut-offs, end strips, and the one panel you ding loading it off the truck
- Divide by sheet area and round up:
ceil(net_with_waste / sheet_area)
Per-wall mode lets you skip the rectangle assumption — useful for L-shapes, knee walls, or when one wall has a sloped ceiling and the formula 2(L+W)H over-counts.
Worked example — 12 × 14 × 8′ master bedroom
Standard configuration: one door, two windows, ceiling included, 4×8 sheets, 10% waste:
- Wall area:
2 × (12 + 14) × 8 = 416 sf - Ceiling area:
12 × 14 = 168 sf - Openings:
1 × 21 + 2 × 12 = 45 sf - Net coverage:
416 + 168 − 45 = 539 sf - With 10% waste:
539 × 1.10 = 592.9 sf - Sheets:
ceil(592.9 / 32) = 19 sheets
Material follow-through at 539 net sf:
- Joint compound:
539 × 0.005 = 2.7 galready-mix (USG All Purpose, three coats) — buy one 3.5 gal pail - Joint tape:
539 × 1.0 = 539 ft— buy three 250 ft rolls - Screws (1¼″ Type W):
539 × 0.01 = 5.4 lb— buy two 5 lb boxes
Sheet-size reference
| Sheet | Area | Best for |
|---|---|---|
| 4 × 8 ft | 32 sf | DIY default — one person can carry, fits any vehicle |
| 4 × 10 ft | 40 sf | 9 ft ceilings without going to 4×12 |
| 4 × 12 ft | 48 sf | Long walls, fewer butt joints, faster finishing for crews of two |
| 54″ × 12 ft | 54 sf | Standard 9 ft ceilings — eliminates the horizontal joint a 4×8 layout forces. Special-order at most yards. |
Thickness — when to upgrade
- 1/4″
- Curved walls, overlay on existing drywall. Not a primary surface.
- 3/8″
- Repairs, archways, manufactured housing. Rare in new construction.
- 1/2″ standard
- The default for residential walls and ceilings on 16″ O.C. studs.
- 1/2″ moisture-resistant
- Bath and kitchen walls. Green board (paper-faced) handles humidity; purple board (Gold Bond XP, USG Mold Tough) is paperless and resists mold growth — pick purple if the wall sees splash, green for general humidity.
- 5/8″ Type X
- Fire-rated, code-required for the garage wall and ceiling shared with living space (IRC R302.6), multi-family party walls, and stairwell soffits. Heavier — count on two carriers.
- 5/8″ soundproof (QuietRock, SilentFX)
- Multi-family party walls and home theaters. Costs 4–8× standard 5/8 — only worth it where STC ratings are written into the spec.
Joint compound — coverage by finish level
| Finish level | Coverage | Use case |
|---|---|---|
| Skim coat (Level 4) | ~0.4 gal / 100 sf | Tape + 2 coats, standard for paint-grade walls |
| Three coat (Level 4 standard) | ~0.5 gal / 100 sf | Calculator default — USG All Purpose ready-mix |
| Level 5 (skim full surface) | ~0.7 gal / 100 sf | Critical lighting, gloss paint, large unbroken walls |
Yields are USG All Purpose Joint Compound published spec. Lightweight (USG Plus 3, Sheetrock UltraLightweight) sands easier and yields 5–8% more square feet per gallon — handy if you are hand-carrying pails up stairs.
Common questions
How much waste should I add?
10% is the residential default and matches what every supplier prints on the spec sheet. Bump to 15% for stair-stepped stair walls, vaulted ceilings, or rooms full of bump-outs and recessed niches. Open-plan ranches with long uninterrupted walls run closer to 5% — if the layout cooperates, the cuts cooperate too.
When do I need 5/8″ Type X (fire-rated)?
The IRC requires it on the wall and ceiling shared between an attached garage and the living space (R302.6), under stairs in multi-story homes, and on multi-family party walls. Code is the floor — many builders use 5/8 throughout the ceiling for sag resistance on 24″ O.C. joists. The thicker board also reads quieter under footfall, which is why upper-floor laundry rooms often spec it. After the drywall is painted, plan the colour with the paint calculator so you order primer and topcoat at the same trip.
Green board, purple board, or DensArmor — which moisture-resistant type?
Green board is paper-faced and humidity-tolerant — fine for a normal bathroom wall away from the tub. Purple board (USG Mold Tough, Gold Bond XP) is also paper-faced but treated against mold for splash zones. DensArmor / DensShield is glass-mat faced (paperless) — the only choice for tile underlayment in showers, since paper can wick water through grout joints over years. The calculator does not change sheet count by type — same 32 sf per 4×8 — but the price field is where the difference lives. You can match the order to the next trade with the concrete calculator when finishing a basement, or the building-design category for the rest of the framing-to-finish stack.
Estimator only. Order from a finalized takeoff against actual room measurements, not from a calculator — wall heights drift on existing framing, and the panel layout decision (vertical vs horizontal hang) shifts cut waste in either direction. For tile or paint follow-on math, see the paint calculator.
