Drywall Square Footage Calculator

Calculate total wall area and find how many drywall sheets you need. Supports 4×8, 4×10, and 4×12 sheet sizes with automatic waste calculation.

Drywall Calculator
Total Wall Area
432
sq ft
Net Area
381
−51 sq ft openings
Sheets Needed
14
4×8 ft sheets
With Waste
16
+10% extra

What is Drywall Square Footage Calculator?

A drywall square footage calculator computes the total wall surface area of a room and converts it into the number of drywall sheets you need to purchase. It accounts for room dimensions, wall height, window and door openings, and a waste factor for cuts and fitting.

This tool exists because drywall is sold in large sheets (4×8, 4×10, or 4×12 feet) and miscounting sheets can halt a project. Running short means an extra delivery and wasted time. Over-buying means storing heavy sheets you do not need. The calculator uses standard window (15 sq ft) and door (21 sq ft) deductions used by professional drywall installers.

Drywall Square Footage Calculator Formula

Sheets = ⌈(Perimeter × Height − Openings) × (1 + Waste%) ÷ Sheet Size⌉

Step 1: Calculate perimeter: 2 × (15 + 12) = 54 ft. Multiply by height: 54 × 8 = 432 sq ft total wall area.

Step 2: Subtract openings: 2 windows (30 sq ft) + 1 door (21 sq ft) = 51 sq ft. Net area = 432 − 51 = 381 sq ft.

Step 3: Add waste and divide by sheet size: 381 × 1.10 ÷ 32 = 13.1 → round up to 14 sheets of 4×8 drywall.

4 ft × 8 ft = 32 sq ft 4 ft × 10 ft = 40 sq ft 4×12 48 sq ft Standard drywall sheet sizes
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Explore our specialized calculators for specific room types, materials estimation, and complex geometric shapes.

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Compute the area of a slanted parallelogram using base length and vertical height.

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Calculate triangle area using base and height, or three sides using Heron's formula.

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Calculate the square footage of walls with a peaked gable roof design (triangular top + rectangular bottom).

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Sq Ft to Sq Meters

Convert area measurements between imperial square feet and metric square meters instantly.

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Frequently Asked Questions

What size drywall sheets are available?
Standard drywall comes in 4×8 ft (32 sq ft), 4×10 ft (40 sq ft), and 4×12 ft (48 sq ft) sheets. The 4×8 sheet is most common for DIY projects. Larger sheets reduce the number of joints but are heavier and harder to handle.
How much waste should I add for drywall?
Add 10% waste for rectangular rooms and 15% waste for rooms with many corners, angles, or cathedral ceilings. The waste accounts for cuts around windows, doors, outlets, and fitting errors.
How do I calculate drywall for ceilings?
Calculate ceiling area as room length × room width. A 12×15 ft room ceiling needs 180 sq ft of drywall. Add this to your wall drywall total. Ceiling drywall is typically 1/2 inch thick.
What thickness of drywall do I need?
Use 1/2 inch drywall for standard walls and ceilings, 5/8 inch for fire-rated walls and ceilings (required between garage and living space), and 1/4 inch for curved walls. This calculator works with any thickness — it calculates area coverage only.
How many screws do I need per sheet of drywall?
Use 28–32 screws per 4×8 sheet. Space screws 12 inches apart on ceilings and 16 inches apart on walls. For a room needing 15 sheets, budget 420–480 drywall screws (about 1 pound of 1-5/8 inch screws).