Drywall Sheet Calculator
Enter wall/ceiling area and waste factor — get sheet count, fasteners, and total weight. Based on KS F 3504 12.5mm standard 900×1800mm.
Result
Enter material and area.
What this tool does
The drywall sheet calculator gives you sheet count, fastener (screw) count, and total weight instantly from wall or ceiling area plus a waste factor. It uses the Korean standard distribution size of 900×1800mm (1.62㎡/sheet) at 12.5mm thickness, and estimates screws with edge spacing 200mm and field spacing 300mm. Know your material quantities before pricing a job to avoid over-ordering.
Who uses this
- New build or renovation interior wall and ceiling drywall sheet count
- Pre-price material quantities and weight for interior fit-out quotes
- Estimate screw quantity for site procurement
- Adjust waste factor for walls with many openings (doors, windows)
- Plan material delivery for high-ceiling commercial or office spaces
How to use (3 steps)
- 1Enter the installation area (m²) — you can combine wall and ceiling areas.
- 2Set the waste factor (%). The default 10% suits straight walls; bump up to 15-20% for angled ceilings or many openings.
- 3Click Calculate to see sheet count (rounded up), fastener count, and total weight with step-by-step workings.
Formula & reference
Sheet spec: 900mm × 1800mm = 1.62㎡/sheet, 12.5mm thick, 16 kg/sheet Adjusted area = installation area × (1 + waste% / 100) Sheet count = ceil(adjusted area ÷ 1.62) Total weight = sheets × 16 kg Fastener estimate (per sheet): Edge screws: ceil(perimeter ÷ 200mm) + 4 Field screws: interior stud rows (stud spacing 600mm) × ceil(sheet length ÷ 300mm) Total fasteners = per-sheet count × sheet count Recommended waste: straight walls 10% / walls with many openings 15% / angled ceilings 20%
Real examples
Example 1: Studio renovation (42㎡ walls)
Adjusted area = 42 × 1.10 = 46.2㎡. Sheets = ceil(46.2 ÷ 1.62) = 29 sheets. Weight = 29 × 16 = 464kg. Approx 580 screws — one 1,000-screw box covers it.
Example 2: Meeting room ceiling (24㎡, 15% waste)
Adjusted area = 27.6㎡. Sheets = ceil(27.6 ÷ 1.62) = 18 sheets. Weight 288kg. 15% used to absorb extra cutting at ceiling perimeter and light fittings.
Example 3: Full apartment interior walls (130㎡)
Adjusted area = 143㎡. Sheets = ceil(143 ÷ 1.62) = 89 sheets. Weight ~1,424kg — plan 2-3 elevator runs for delivery in multi-story buildings.
Frequently asked questions
Which size is standard — 900×1800mm or 1220×2440mm (4×8)?
900×1800mm (1.62㎡) is the primary distribution size in Korea. North American standard is 4×8 ft (1220×2440mm, 2.976㎡). Always check the project specification. This calculator uses the Korean 900×1800mm size.
How do I choose between 9.5mm and 12.5mm thickness?
9.5mm (12kg/sheet) is used for lightweight partitions and ceilings. 12.5mm (16kg/sheet) suits load-bearing walls, fire-rated assemblies, and walls adjacent to wet areas. Regulatory fire-compartment requirements often specify 12.5mm minimum.
Is 10% waste enough?
Yes for straight walls with few openings. Use 15% where doors and windows are frequent, and 20% for angled or irregular ceilings. Under-ordering risks a colour-lot mismatch if you reorder later.
What spacing rules are used for fastener estimates?
Edge screws at 200mm intervals, field screws at 300mm intervals, stud spacing 600mm assumed. This gives roughly 20 screws per sheet; actual count varies with real stud layout.
Why does the result include weight?
Weight matters for load assessments, elevator capacity planning, and selecting lightweight steel framing. At 89 sheets of 12.5mm drywall, you are moving about 1,400kg — typically 2-3 trips in a small elevator.
Can I add wall and ceiling areas together?
Yes, but waste rates differ — walls typically 10%, ceilings 15-20%. For the most accurate result, calculate walls and ceilings separately and add the sheet counts.
Cautions
- •Based on Korean 900×1800mm distribution size. Imported or non-standard sizes need separate conversion.
- •Fastener count assumes 600mm stud spacing — verify against actual framing layout on site.
- •Wet areas (bathrooms, kitchens) require moisture-resistant drywall (green board) or cement board, not standard gypsum.
- •Fire-rated assemblies require specific thickness and fire rating confirmation beyond this calculator.
- •Sheet count is always rounded up, so expect a small surplus.
Last reviewed: 2026-06-17