Drywall / Gypsum Board Calculator

Drywall is a construction staple precisely because it is a quick, repeatable way to make a flat wall. But the ordering math quietly surprises people: a 12×10 ft room sounds small until you add up two 12 ft walls, two 10 ft walls and a ceiling, subtract doors and windows, and discover you need a full stack of 4×8 sheets, a box of screws, several buckets of mud and a roll of tape before anyone lifts a sheet.

Drywall Calculator turns a room into a complete materials list: gypsum sheets, drywall screws, joint tape, joint compound and corner bead. It accounts for doors and windows, supports standard and tall board sizes in both imperial and metric units, and includes a dedicated wet-area switch so the report can flag moisture-resistant board where it matters. A 10-percent waste default keeps the estimate honest against real cuts and breakage.

The learning guide walks through sheet sizes, screw spacing patterns, three-coat finishing, and which thickness to choose for fire-rated and moisture jobs. Everything runs in the browser — nothing is uploaded.

• Room or area input: Enter length, width and wall height to get walls plus ceiling automatically, or switch to a direct-area mode for odd spaces.
• Doors & windows: One field for total opening area keeps the estimate honest against real openings.
• Board sizes: 4×8, 4×10, 4×12, 4×14 ft and the metric 1200×2400, 1200×2700, 1200×3000 mm options.
• Full materials list: Sheets, screws, joint tape in feet, joint compound in gallons, and corner bead in feet — everything one trip to the supplier needs.
• Wet-area switch: Flag bathrooms and laundry rooms so the report notes moisture-resistant board.
• Waste adjustment: Default 10 percent for cuts and damage, adjustable to your layout.
• Wall height presets: 8, 9, 10 and 12 ft, or metric 2.4–3.0 m, matching standard board runs.
• Live estimate: Sheet count and total board area update as you type, with the maths shown step by step.
• Export: Copy or download the full materials report as text, CSV or JSON.
• Learning guide: Screw-spacing table, finishing coats, board-type guide and practical hanging tips.

1. Pick the unit system. Feet/inches for US-style 4×8 sheet estimates or metres for 1200 mm metric boards.
2. Enter room length, width and wall height. The tool adds both lengths of wall, the two width walls and the ceiling automatically.
3. Subtract openings. Add up the total door and window areas (roughly 20 sq ft per door, 12–15 sq ft per window) and enter the sum.
4. Choose the board size. 4×8 is standard; taller rooms gain from 4×10 or 4×12 to reduce joints.
5. Flag wet areas. Toggle the moisture-resistant switch for bathrooms, laundry and basements.
6. Set waste. Leave 10 percent for cuts and breakage or reduce it on simple boxes.
7. Read the estimate. Sheet count, board area and the screw, tape, compound and bead quantities appear instantly.
8. Review the working. The maths line shows gross area, opening deduction, and division by sheet area.
9. Export the report. Copy or download as text, CSV or JSON to take to the supplier.
10. Check the guide. The learning tab explains screw spacing, finishing coats and board types.

Example 1 — Standard bedroom. A 12×10 ft room with 8 ft walls: walls are 2×(12+10)×8 = 352 sq ft, ceiling 120 sq ft. Subtract a 20 sq ft door and two 15 sq ft windows. Net ≈ 422 sq ft → about 14 sheets of 4×8, ~425 screws, ~70 ft of tape and ~28 gallons of compound.

Example 2 — Tall ceiling living room. A 20×16 ft room with 10 ft walls: walls 2×(20+16)×10 = 720 sq ft plus 320 sq ft ceiling, minus 35 sq ft openings. About 32 sheets of 4×10 board keeps horizontal joints to a minimum.

Example 3 — Bathroom wet area. A 7×5 ft bathroom with 8 ft walls and a tub: net ~180 sq ft of drywall. With the wet-area switch on, the report recommends moisture-resistant board for the surround and notes standard board for the remainder.

Example 4 — Direct area, shed. A 240 sq ft wall run at 9 ft with a 30 sq ft door and window: net 210 sq ft → 7 sheets of 4×8 and roughly 210 screws with 20 ft of corner bead.

Example 5 — Whole-house budget. 2,400 sq ft of finished board at 1 screw per sq ft means ~2,400 screws (about 8 boxes of 300), ~400 ft of tape, and ~150 gallons of compound — the calculator rolls every room into one order.

• One order, one trip: Sheets, screws, tape, compound and bead in a single list with no double-counting.
• No dead-end at the supplier: The sheet size dropdown matches local stock, so the count is for the product that is actually on the shelf.
• Right board for the room: The wet-area switch and board-type guide keep moisture and fire-rated jobs from being underspecified.
• Honest with openings: Doors and windows are subtracted, and waste is added, so neither the budget nor the pile surprises you.
• Metric and imperial: Switches between 4×8 ft sheets and 1200 mm boards without mental conversions.
• Explainable numbers: The working line shows gross, deduction and sheet division so nothing is a black box.
• Export-ready: Text, CSV and JSON reports drop into quotes, purchase orders and spreadsheets.
• Free and private: No uploads, no accounts, no logging.