Room Dimensions
Enter the length, width, and height of the room you are drywalling.
Doors & Windows
These areas will be subtracted from the total wall surface. Leave at 0 if none.
Sheet Size & Waste
Choose your drywall sheet size and add a waste percentage to account for offcuts.
Cost Estimate (optional)
Enter sheet price and optional material rates for a full project cost estimate.
Drywall Sheet Size Reference
Common US drywall sheet sizes with typical prices and best use cases.
| Sheet Size | Area (sq ft) | Typical Price | Best Use |
|---|---|---|---|
| 4 ft × 8 ft | 32 | $6 – $8 | Small rooms, repairs, curved areas |
| 4 ft × 9 ft | 36 | $9 – $11 | 9 ft ceilings, standard walls |
| 4 ft × 10 ft | 40 | $10 – $12 | Standard walls and ceilings |
| 4 ft × 12 ft | 48 | $10 – $14 | Large rooms, fewer seams needed |
Drywall Thickness Guide
Choose the right thickness for your application.
| Thickness | Metric | Best Application |
|---|---|---|
| 1/4 inch | 6.5 mm | Curved walls, renovation over existing surface |
| 3/8 inch | 9.5 mm | Ceiling renovation, lightweight applications |
| 1/2 inch | 12.5 mm | Standard interior walls — most common choice |
| 5/8 inch | 15.9 mm | Fire-resistant (Type X), soundproofing, ceilings |
| 3/4 inch | 19 mm | Heavy-duty fire and sound applications |
How to Calculate Drywall
Step 1 — Calculate Total Wall Area
Add up the area of all four walls plus the ceiling (if included). For a rectangular room:
Step 2 — Subtract Openings
Subtract the area covered by doors and windows so you don’t buy excess sheets.
Step 3 — Apply Waste Factor
A 10% waste factor is standard for straightforward rooms. Use 15% for rooms with many cuts (lots of corners, outlets, irregular shapes).
Step 4 — Estimate Screws & Joint Compound
Tips for Buying Drywall
Always round up to the nearest whole sheet — you cannot buy fractions. Use larger sheets (4×12) in big rooms to reduce the number of seams, which means less taping and finishing work. Choose 4×8 sheets for small or irregular spaces where maneuverability matters.