Drywall Calculator
Estimate drywall sheets for room walls and an optional ceiling, plus approximate screws and joint compound.
What this calculator does
The calculator adds wall area and an optional ceiling, divides by standard sheet coverage, and rounds up to whole sheets after applying waste.
Drywall coverage
Sheet totals use 4 × 8 ft sheets. Compound uses approximately 1 US gallon per 100 ft²; actual finishing level and seam layout can change usage.
Wall and optional ceiling areas are divided by one sheet area, then the selected waste percentage is applied and rounded up.
The arithmetic uses the exact values shown above. Verify field measurements, product pack sizes, layout constraints, and local requirements before ordering or building.
How to interpret the result
Sheet count is a planning quantity. Orientation, seams, openings, fire or moisture ratings, finish level, framing, and local code requirements can change the material list.
How the result is calculated
Total area = wall area + optional ceiling area. Sheets = total area ÷ sheet area × (1 + waste %), rounded up.
Worked example
A 14 × 12 × 8 ft room with its ceiling included contains 584 ft² of coverage before waste.
How to use this calculator
- Measure room length, width, and finished height.
- Choose whether the ceiling is included.
- Select a waste allowance suited to openings and layout.
- Plan sheet orientation before ordering.
- Confirm board type, thickness, fastening, and finish requirements.
Supported units
Feet and 4 × 8 ft sheets in imperial mode; meters and 1.2 × 2.4 m sheets in metric mode.
Practical guidance
- Plan sheet orientation before ordering.
- Add waste for many openings or complicated corners.
- Confirm fire, moisture, and thickness requirements.
Assumptions and limitations
Standard 4 × 8 ft or 1.2 × 2.4 m sheets are assumed. Openings are not deducted because offcuts are often reused and small deductions can understate waste.
Methodology
Wall perimeter × height gives wall area. Optional ceiling area is added, waste is applied, and total coverage is divided by standard sheet area.
Read the complete calculation methodology and testing policy.
Sources and technical references
References support terminology, units, or practical constraints. They do not imply endorsement or project approval.
- NIST Special Publication 811 — Guide for the Use of the International System of UnitsReference for SI units, symbols, and conversion-factor practice.
- Gypsum Association — What is Gypsum Board?Industry background on gypsum board products and their intended wall and ceiling uses.
Frequently asked questions
Why are doors and windows not deducted?
Conservative sheet planning often keeps those areas because cuts and offcuts affect usable coverage.
How many screws are estimated?
The optional planning figure uses 32 screws per sheet; fastening schedules vary.
Is joint compound exact?
No. It is a broad planning estimate affected by finish level and installer technique.