How many sheets of drywall do I need?

Calculate the total square footage of your walls and ceiling, then divide by 32 (for 4x8 sheets) or 48 (for 4x12 sheets). Add 10-15% for waste from cuts and mistakes. A standard 12x12 room with 8-foot ceilings needs about 18 sheets for the walls alone.

What size drywall should I use?

Use 1/2-inch drywall for most walls and ceilings with framing spaced 16 inches on center. Use 5/8-inch for ceilings with 24-inch framing or where fire rating is required. Use 1/4-inch for curved walls. Moisture-resistant (green board) is used in bathrooms.

How do I calculate drywall for a room?

Measure each wall's width and height, multiply to get square footage, then add all walls together. Subtract door and window openings. Add the ceiling area if finishing it. Divide the total by 32 sq ft per 4x8 sheet and add 10% for waste.

How much does drywall cost per sheet?

Standard 1/2-inch 4x8 drywall costs $12-$18 per sheet. Moisture-resistant drywall runs $14-$22, and fire-rated 5/8-inch costs $15-$25 per sheet. Professional installation adds $1.50-$3.50 per square foot for hanging, taping, and finishing.

Drywall Calculator

Calculate drywall sheets, joint compound (in buckets), tape, screws, and corner bead for single or multi-room projects. Includes material cost estimates and practical purchasing units.

Drywall Type

Sheet Size

Waste Factor (%)

Corner Bead Length (ft)

Room Name

Room Length (feet)

Room Width (feet)

Ceiling Height (feet)

Number of Doors

Number of Windows

Outside Corners

Common in hallways, soffits, and additions

Include Ceiling

Material List

Total Area

436

sq ft

Drywall Sheets

4x8 1/2" Regular

Sheets Include

10%

waste factor

Finishing Materials

All-Purpose Joint Compound

bucket (4.5 gal / ~58 lbs each)

Covers taping, fill, and finish coats

Setting-Type Compound

bag (18 lb)

For first/embed coat — sets chemically, won't shrink

Drywall Screws

box (1 lb / ~200 screws)

1-5/8" coarse thread for 1/2" drywall

Paper Tape

roll (500 ft each)

Standard — use with all-purpose compound

OR Fiberglass Mesh Tape

rolls (300 ft each)

Self-adhesive — must use with setting-type compound

Corner Bead

Inside Corner Bead (Paper-Faced)

pieces (8 ft each)

32 linear ft total

Estimated Material Cost

Total Materials

$239– $284

Based on typical supply house pricing for 1/2" Regular

Sheets: $180–$225

Compound: ~$30

Tape: ~$5

Screws: ~$8

Corner Bead: ~$16

Pro Tips from the Field

Hang Sheets Horizontally

Hang sheets horizontally on walls to reduce visible seams. The tapered long edges create a shallow channel that's much easier to finish flat than butt joints.

Fire Code Requirements

Use 5/8" Type X on garage walls and ceilings adjacent to living spaces per fire code (IRC R302.6). Check local codes for additional requirements.

Moisture-Resistant Board

Green board is required in bathrooms but NOT in shower surrounds — use cement board or Kerdi membrane in wet areas. Green board handles humidity, not direct water.

Order Extra Material

Order 10-15% extra — cutting around outlets, fixtures, and odd angles creates waste. Running short mid-job costs more in downtime than a few extra sheets.

Screw Spacing Matters

Field screws every 16" on ceilings, 12" on walls. Edge screws every 8" on ceilings, 12" on walls. Keep screws 3/8" from edges to avoid crumbling.

Setting Compound for First Coat

Use setting-type (hot mud) for embedding tape — it sets chemically and won't shrink or bubble. Switch to all-purpose for fill and finish coats for easier sanding.

Did this help?

How to Use This Calculator

Enter dimensions for each room including ceiling height, doors, and windows. Add multiple rooms for whole-house estimates. Choose your drywall type and sheet size. The calculator provides a complete material list in the units you actually buy at the supply house — buckets, boxes, and rolls.

Formula Used

Wall Area = 2 x (Length + Width) x Ceiling Height - Door Openings - Window Openings. Sheets = Total Sq Ft x (1 + Waste%) / Sheet Sq Ft. Compound = Total Sq Ft / 460 sq ft per 4.5-gal bucket (3 coats). Screws = Total Sq Ft x 0.32, sold in 1-lb boxes (~200 screws).

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Disclaimer

This calculator is for estimation purposes only. Results may vary based on local conditions, materials, and building codes. Always consult a licensed professional before making decisions based on these calculations. MyContractorTools is not responsible for any errors or omissions.