Drywall Calculator
Area to sheets, plus screws, tape and mud.
Also known as plasterboard sheets · gypsum board sheets · sheet count
With the default inputs: Wall and ceiling area 800 ft² · Sheet size 4 × 8 ft · Layers Single layer etc.Drywall sheets 28 sheets
Use your own dimensions ↓Inputs
Result
| Area per sheet | 32ft² |
| Layers | 1layers |
| Area with waste | 880ft² |
| Screws (approx) | 2.8lb |
| Tape (500 ft rolls) | 2rolls |
| Joint compound (approx) | 4.4gal |
| Mud in 4.5 gal buckets | 1cans |
How this is worked out
Sheets = area x layers x (1 + waste) ÷ sheet area, rounded up. 10% waste is the norm; busy plans with many openings or irregular ceilings go to 15%, and a clean large flat ceiling takes 5-8%. The sundries are estimates: about 32 screws per 4x8 sheet with roughly 320 screws to the pound, tape at about 500 ft² per 500 ft roll, and mud at about 0.5 gal per 100 ft² for a three-coat finish. Real usage depends heavily on joint density - the same area in small rooms has twice the joints, so mud can double. Buckets of 4.5 gal are cheaper than small boxes and keep well sealed. Longer sheets mean fewer joints and faster work: 4x12 costs more than 4x8 but usually wins on mud and labour.
Next up: Skirting Board Calculator · Plasterboard Quantity Calculator
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Formula
| Sheets = area × layers × (1+waste) ÷ sheet area | round up |
| Screws (lb) = sheets × 32 ÷ 320 | 32 per sheet, 320 per lb |
| Tape rolls = area ÷ 500 | a 500 ft roll does about 500 ft² |
| Mud (gal) = area ÷ 100 × 0.5 | three-coat finish |
How to work it out
- Measure walls (perimeter x clear height, less openings) and ceilings, and add them for total area.
- Pick the sheet size: 4x8 is the default, 4x12 means fewer joints but weighs about 65 lb (30 kg).
- Sheets = area x layers x (1 + waste) ÷ sheet area, rounded up.
- Estimate sundries by ratio: about 32 screws per sheet, one 500 ft tape roll per 500 ft² and 0.5 gal of mud per 100 ft².
- Order long sheets for big flat ceilings and short ones for the cut-heavy areas.
Where it goes wrong
- Multiplying floor area by a factor - the factor swings between 2.5 and 3.5, which is up to 30% error either way.
- Driving screws through the paper - it loses holding power and mud will not hide it; the most common drywall defect.
- Butting sheets tight with no 1/8 in gap - panels move with humidity and the joint buckles, worst on long ceilings.
Material and cost
Half-inch standard board is about USD 0.40-0.60 per ft², so a 4x8 sheet is 13-19. Moisture-resistant board costs 20-30% more and Type X fire-rated 30-50% more. A 4.5 gal bucket of mud is 15-25 and a 500 ft roll of tape 5-10. Hanging and finishing labour runs USD 1.50-3.50 per ft², far more than the materials.
On site
- Joints over 12 ft, especially on ceilings, crack first - run sheets perpendicular to the joists so long joints are broken up.
- Use 5/8 in board on ceilings: stiffer, sags less, better acoustically, and barely dearer.
- Spot-prime every screw head before mudding or rust blooms through in a few years - the most common callback.
Basis
- EN 520:2004+A1:2009 Gypsum plasterboards — Definitions, requirements and test methods
- BS 8212:1995 (dry lining, board thickness and fixing centres)
- ASTM C840 (application and finishing of gypsum board, US)
- IS 2095-1:2011 Gypsum Plaster Boards — Specification
FAQ
How should I measure the area?
4x8 or 4x12 sheets?
How many screws per sheet?
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Drywall Calculator. 2026-10-25. https://jianzhujisuan.com/en/drywall-sheets