Free tool

Drywall Calculator

Estimate how many drywall sheets, screws, and buckets of joint compound a room needs. Enter the area or the room dimensions, pick a sheet size, and add a waste allowance.

Drywall material calculator

Add up every surface you plan to cover. Not sure of the area? Use the square footage calculator first.

Drywall sheets needed

14

4×8 ft sheets · 400 sq ft + 10% waste

Wall / ceiling area400 sq ft
With waste+10%440 sq ft
Sheets14
Drywall screws1¼–1⅝ in~448
Joint compoundtape + 3 coats2 × 5-gal

Estimates are gross (no deductions for doors or windows); the waste allowance covers cuts and offcuts. Buy the next full sheet, bucket, and screw box up.

How to estimate drywall for a room

Drywall math is straightforward once you have the area. Measure the surfaces you plan to cover, divide by how much one sheet covers, and add a cushion for waste:

  • Find the area. For four walls, area is 2 × (length + width) × ceiling height. Add length × width again if you are also hanging the ceiling. The calculator computes both for you in the room-dimensions tab.
  • Pick a sheet size. A 4×8 sheet covers 32 sq ft; a 4×12 covers 48 sq ft. Bigger sheets mean fewer seams but more weight to lift.
  • Add waste, then round up. Sheets = area × (1 + waste ÷ 100) ÷ sheet coverage, rounded up to the next whole sheet. You cannot buy a partial sheet, and offcuts add up fast.

Need the raw square footage first? Run the square footage calculator and drop the total into the area tab above.

Screws and joint compound

Fasteners and mud are easy to underbuy. At 16-inch stud spacing you use roughly one screw per square foot of sheet, so a 4×8 takes about 32 screws and a 4×12 about 48. For finishing, budget about one 5-gallon bucket of all-purpose joint compound per 400 sq ft to tape the seams and lay three coats. Textured walls, level-5 finishes, and hot climates that dry mud fast all push that number up, so keep an extra bucket on hand.

Pricing the job, not just the materials

Material counts are the starting point, not the quote. A profitable drywall or remodel job also covers labor hours, delivery, dumpster and disposal, and your overhead and margin. If you are hanging and finishing drywall for customers, see how to start a handyman business for the licensing and pricing side, and how to start a painting business if drywall is a lead-in to paint work. Then turn the material list into a real number with the job pricing calculator. Browse every free estimator on the tools page.

Frequently asked questions

How many sheets of drywall do I need?

Divide your total wall and ceiling area by the coverage of one sheet (32 sq ft for a 4x8, 48 sq ft for a 4x12), then add a waste allowance and round up. For example, 400 sq ft with 4x8 sheets and 10% waste is ceil(440 / 32) = 14 sheets. The calculator does this for you and also estimates screws and joint compound.

How much drywall waste should I add?

Ten percent is a safe default for a straightforward room. Add more (12–15%) for spaces with lots of doors, windows, angles, or short walls where you cut more and use less of each sheet, and less (5–8%) for large, open, rectangular rooms. The waste allowance covers offcuts, mistakes, and damaged sheets.

How many screws and how much joint compound per sheet?

Plan on roughly one screw per square foot of sheet at 16-inch stud spacing, so about 32 screws for a 4x8 sheet and 48 for a 4x12. For joint compound, budget about one 5-gallon bucket of ready-mix per 400 sq ft to tape and apply three finish coats. Textured or level-5 finishes use more.

Should I use 4x8 or 4x12 drywall sheets?

Longer 4x12 sheets cover more area with fewer seams, which means less taping and a flatter finish, but they are heavier and harder to handle solo. 4x8 sheets are easier for one person and fit through tight spaces. Pick the size in the calculator and compare the sheet counts.

Is this drywall calculator free?

Yes. The drywall calculator is completely free, with no signup and no credit card. It runs entirely in your browser. When you are ready to quote the job and schedule the crew, Fieldtics has a free tier too.

Estimate it here, run the job in Fieldtics

Count the materials here, then run the job in Fieldtics — quotes, scheduling, and invoicing in one free app. The free tier covers unlimited clients, job scheduling, a customer CRM, and the mobile app with no credit card. The $29/mo Professional tier adds quotes, invoicing, online payments, and team scheduling. Trusted by 500+ service businesses.