How much joint compound do I need for drywall?

A general rule is one gallon of joint compound per 100 square feet of drywall. For a standard room, that typically means two to four buckets (4.5 gallons each). This calculator estimates compound based on your actual square footage.

How many drywall screws per sheet?

Plan for approximately 32 screws per 4×8 sheet when fastening to studs 16 inches on center. That equals roughly one screw per square foot of drywall.

What size drywall sheet should I use?

4×8 sheets (32 sq ft) are the standard and easiest to handle alone. 4×12 sheets (48 sq ft) reduce the number of seams and are preferred by professionals for ceilings and long walls, but require two people to install.

Drywall Calculator — Sheets, Mud & Screws

Quick Answer Add each wall and your ceiling. The calculator totals the square footage, subtracts door and window openings, adds a 10% waste factor, then outputs sheets, compound, screws, and tape. Change the sheet size to 4×12 if your project uses them.

Free Estimator

Drywall Material Calculator

Add walls and ceilings, subtract openings, pick your sheet size — get your full material list in seconds.

Walls

Length (ft)

Height (ft)

Count

Ceiling (optional)

Length (ft)

Width (ft)

Deductions (openings)

Each standard door ≈ 21 sq ft · Each window ≈ 15 sq ft. Or enter custom sq ft.

Doors

Windows

Custom deduction (sq ft)

Sheet Size

Sheet size

Waste factor

Your Material Estimate

Drywall Sheets

—

4×8 sheets

Net Area

—

sq ft (after deductions)

Joint Compound

—

gallons (~4.5 gal buckets: —)

Drywall Screws

—

screws (1-lb boxes: —)

Joint Tape

—

linear ft of tape needed

Area with Waste

—

sq ft (including waste factor)

How to Use This Calculator

Add one row per unique wall dimension. If you have two walls that are both 12 ft × 9 ft, enter Length 12, Height 9, Count 2 — rather than adding two identical rows. For the ceiling, enter the room length and width. Openings are subtracted automatically.

Pro tip — sheet orientation Hang drywall horizontally on walls whenever possible. Horizontal installation reduces the number of butt joints (the harder seams to finish), puts the tapered edges at a comfortable working height, and is structurally stronger. On 9-ft walls you'll need a third course; 8-ft walls work cleanly with horizontal 4×8 sheets.

Drywall Material Reference

Material	Coverage Rule	Notes
4×8 Drywall Sheet	32 sq ft per sheet	Standard residential. Easiest to handle solo.
4×12 Drywall Sheet	48 sq ft per sheet	Fewer seams. Preferred for ceilings. Requires two people.
Joint Compound (pre-mixed)	~1 gal per 100 sq ft	Buy pre-mixed for most jobs. Easier to sand, slower to dry.
Paper Joint Tape	~1 linear ft per sq ft	Stronger than mesh for flat seams. Requires embedding coat.
Drywall Screws (1-5/8")	~32 per 4×8 sheet	Studs 16" OC. Add 10% for edges and corners.
Corner Bead	1 piece per outside corner	Metal or vinyl. Not included in calculator — count manually.

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Frequently Asked Questions

How many sheets of drywall do I need?

Divide your net square footage (after subtracting openings) by the sheet size — 32 for 4×8, 48 for 4×12 — and add 10% for waste. This calculator does that automatically.

How much joint compound do I need?

Budget approximately one gallon of joint compound per 100 square feet of drywall. Pre-mixed compound comes in 4.5-gallon buckets. Most single-room jobs need one to two buckets; full house projects can require five or more.

What is the difference between 4×8 and 4×12 drywall?

4×8 sheets are lighter, easier to handle alone, and available everywhere. 4×12 sheets cover 50% more area per sheet, which means fewer seams and a better-looking finish — but they weigh about 54 lbs and really need two people to install safely, especially on ceilings.

Should I add a waste factor?

Yes. Even for simple rectangular rooms, cuts at outlets, switches, and corners add up. 10% is the standard waste factor for typical rooms. Use 15% for rooms with many windows, angles, or complex cuts.

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Drywall Calculator —Sheets, Mud & Screws

How to Use This Calculator

Drywall Material Reference

Frequently Asked Questions

Deep guides for every challenge

Drywall Calculator —
Sheets, Mud & Screws