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Drywall Calculator
Drywall Calculator
Material Calculators

Drywall Calculator

Calculate drywall sheets, joint compound, tape, and screws for any room.

DIY difficulty

ModerateTypical time: 2–3 weekends
  • ›Hanging sheets is manageable with a helper
  • ›Taping and mudding (3 coats minimum) takes skill to get smooth
  • ›Sanding drywall compound is messy — seal the room

Must-have tools

Drywall lift or helperScrew gunMud pan and taping knivesSander and respirator

How to calculate drywall for a room

  1. Enter each wall's length and height, along with the number of doors and windows. The calculator subtracts standard rough opening sizes automatically.

  2. Choose your sheet size — 4×8 is standard, 4×12 works better for long wall runs and reduces seams.

  3. Read the sheet count, joint compound (mud), tape, and screw estimates.

  4. Add 10% for waste, cuts, and damaged corners. Partial sheets still count as full purchases at the store.

Common uses

  • Finishing a basement or garage conversion
  • Replacing drywall after water damage or renovation
  • Estimating material for a new room addition

Frequently asked questions

How many sheets of drywall do I need for a 12×12 room?
A 12×12 room with 8-foot ceilings takes roughly 18–20 sheets of 4×8 drywall for the walls, plus 4 sheets for the ceiling — about 22–24 total before waste.
What's the difference between 1/2-inch and 5/8-inch drywall?
Half-inch is standard for most interior walls. Five-eighths-inch is required by code for garage walls and ceilings adjacent to living space because of its fire resistance.
How much joint compound do I need?
A rough rule is 1 gallon of pre-mixed mud per 100 square feet of drywall. You'll typically apply three coats — tape coat, filler coat, and finish coat.
Should I hang drywall horizontally or vertically?
Horizontal is standard for walls — it reduces the number of butt joints (which are harder to finish) and the long edges fall at the same height for consistent mudding.
Do I need to tape all drywall seams?
Yes — all tapered joints and butt joints need paper tape embedded in joint compound. Mesh tape is easier to apply but produces weaker joints; use paper tape for flat walls.

Common mistakes to avoid

  • ✕Not sealing the room before sanding — drywall compound dust is extremely fine. Hang plastic sheeting over every doorway first.
  • ✕Skimping on mud coats — three coats minimum (tape, filler, skim). Rushing to two coats always shows ridges under paint.
  • ✕Wrong thickness — 1/2" for standard walls; 5/8" is required by IRC for any wall adjacent to a garage.
  • ✕Not marking outlet locations before hanging — retrofitting cuts in hung drywall is significantly harder.

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Not sure whether to DIY this project?

Read our project-by-project guide on when to hire a contractor vs. do it yourself.

Read the guide →

About this calculator

Enter your wall dimensions to get the exact number of drywall sheets (4×8 or 4×12), gallons of joint compound, feet of tape, and screw count. Accounts for doors and windows.

All results are estimates. Verify quantities with your local supplier and confirm measurements before purchasing materials. Requirements vary by region and project type.

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