Drywall Calculator

Estimate how many drywall sheets, screws, tape and joint compound you need for walls and ceilings.

Last updated: September 2026 · Reviewed for standard drywall sheet and finishing estimates

Room Dimensions

Length

Width

Ceiling Height

Include ceiling

Openings

Number of Doors

Number of Windows

Sheet Options

Sheet Size

Waste Factor

Price per Sheet (optional)

How to Use This Drywall Calculator

Enter room length, width and ceiling height
Check Include ceiling if you are hanging drywall on the ceiling
Enter number of doors and windows (subtracted from wall area)
Choose sheet size (usually 4×8) and waste factor
Click Calculate Drywall for sheets plus rough screw, tape and mud estimates

Common Room Examples (4×8 Sheets, 10% Waste, 1 Door + 2 Windows)

Quick reference for typical rooms. Sheets rounded up. Ceiling not included unless noted.

Room Size	Walls Only	Walls + Ceiling
10 × 12 ft (8 ft high)	~11 sheets	~15 sheets
12 × 15 ft (8 ft high)	~14 sheets	~20 sheets
15 × 20 ft (8 ft high)	~19 sheets	~29 sheets
20 × 20 ft (9 ft high)	~25 sheets	~38 sheets

Always re-calculate with your exact openings and sheet size. Buy a few extra sheets for cuts and damage.

Standard Sheet Sizes

Sheet Size	Area	Common Use
4 × 8 ft	32 sq ft	Most walls and ceilings
4 × 10 ft	40 sq ft	Taller walls, fewer seams
4 × 12 ft	48 sq ft	Long walls, fewer joints

Typical thickness: ½" walls, ⅝" ceilings or fire-rated assemblies.

Formulas Used

Wall area = 2 × (Length + Width) × Height − (Doors × 20) − (Windows × 15)

Ceiling area = Length × Width (if included)

Sheets = ceil((Total area × (1 + Waste%)) ÷ Sheet area)

Screws (walls) ≈ Wall area with waste × 1 (about 32 per 4×8 sheet)

Screws (ceiling) ≈ Ceiling area with waste × 1.4 (about 45 per 4×8 sheet)

Tape and joint compound amounts are rule-of-thumb estimates for planning.

Drywall Screw Requirements

Screw count depends on surface and spacing. This calculator uses industry planning rates:

Surface	Typical spacing	Rate used	Per 4×8 sheet (approx)
Walls	12" edges, 16" field	~1 screw / sq ft	~32
Ceilings	12" edges & field	~1.4 screws / sq ft	~45

Use 1-1/4" screws for 1/2" drywall into wood; longer for thicker board or ceilings as required
Drive screws just below the paper — do not tear the face paper
Buy a little extra; count per box/lb varies by brand
Always follow local code and manufacturer fastening schedules for fire-rated assemblies

Drywall Tips

Hang sheets perpendicular to framing when possible for strength
Stagger seams so joints do not line up
Use 5/8" on ceilings for less sag
Drive screws just below the paper surface — do not break the face paper
Plan for 3 coats of joint compound on most seams for a smooth finish

Frequently Asked Questions

How many drywall sheets do I need?

Calculate wall and ceiling area, subtract doors and windows, add about 10% waste, then divide by sheet size (32 sq ft for 4×8). Round up to whole sheets. This calculator does it automatically.

What size are standard drywall sheets?

The most common sheet is 4×8 feet (32 sq ft). Other sizes include 4×10 and 4×12. Thickness is typically ½" for walls and ⅝" for ceilings or fire-rated areas.

How much joint compound do I need?

A common rule is about 0.05–0.08 gallons per sq ft for taping and finishing. Many pros use roughly one 5-gallon bucket per 500–1000 sq ft, depending on finish level.

How much drywall tape do I need?

Estimate about 0.4 linear feet of tape per sq ft of drywall, or roughly one 500-ft roll per 10–12 sheets. Exact needs depend on layout and number of seams.

Should I include the ceiling?

Yes, if you are hanging drywall on the ceiling. Check “Include ceiling” so the calculator adds that area and sheet count.

How do I account for doors and windows?

Enter the number of doors and windows. The calculator subtracts about 20 sq ft per door and 15 sq ft per window so you do not over-order sheets.

How many screws per sheet?

On walls, plan about 1 screw per sq ft (~32 per 4×8 sheet) with 12" edge and 16" field spacing. On ceilings, use closer spacing (~1.4 per sq ft, ~45 per 4×8). This calculator applies those rates separately when you include the ceiling.

How many drywall screws do I need for a room?

Multiply wall area (with waste) by ~1, and ceiling area (with waste) by ~1.4, then add them. Example: 300 sq ft walls + 120 sq ft ceiling ≈ 300 + 168 = ~470 screws. Always buy a bit extra.

Related measurements

After hanging drywall, estimate paint with the paint calculator. Room area: square footage calculator. Floor finish: flooring calculator. Browse all construction calculators.