Drywall Calculator
Estimate drywall sheets, screws, compound, tape, materials, labor, and project cost.
Room Dimensions
Doors & Windows
Drywall Options
Standard Drywall Sizes
Easiest to handle; the DIY standard.
Fewer butt joints on 9–10 ft walls.
Pro choice — minimizes seams & finishing.
Long walls & commercial work; needs a crew.
Very long spans; heavy, hard to maneuver.
Drywall Thickness Guide
Curved walls, skim-over resurfacing, arches.
Repairs and remodels over existing plaster.
Standard for walls and 16" o.c. ceilings.
Fire-rated walls, garages, 24" o.c. ceilings.
What Is Drywall?
Drywall — also called sheetrock, gypsum board, plasterboard, or wallboard — is a panel of gypsum plaster pressed between two sheets of heavy paper. It is the standard interior wall and ceiling surface in modern homes because it installs fast, resists fire, and provides a smooth base for paint. A finished drywall job means hanging the sheets, driving screws into the framing, taping the seams, and applying three coats of joint compound before sanding smooth.
This calculator turns your room dimensions into a complete material list and cost estimate. To plan the rest of the project, pair it with our Area Calculator for square footage, the Tile Calculator for finishes, the Concrete Calculator for footings, and the Board Foot Calculator for framing lumber.
How to Calculate Drywall
Measure every surface
For walls, multiply each wall's length by its height; for a room, use the perimeter times the wall height. For ceilings, multiply length by width. Add all surfaces together for the gross area in square feet.
Subtract doors and windows
Openings don't get drywalled, so their area is deducted from the wall total. A standard door is about 20 sq ft and a window about 12 sq ft. Enter each one and the calculator removes it automatically.
Divide by the sheet size
Divide the net area by one sheet's area — 32 sq ft for a 4×8, 48 sq ft for a 4×12 — then round up. Larger sheets cover more wall with fewer seams to tape and sand.
Add waste and materials
Apply a waste factor (about 10% for most rooms) for offcuts and repairs, then layer in the supporting materials: screws, joint compound, tape, and corner bead, plus labor and cost.
How Many Drywall Sheets Do I Need?
Start with the total surface area, subtract openings, add waste, and divide by the sheet size. For a simple 12 × 12 ft room with 8 ft walls, the four walls total about 384 sq ft and the ceiling adds 144 sq ft. Take out roughly 32 sq ft for a door and a window, add a 10% waste factor, and you need about 545 sq ft of drywall — that is 18 sheets of 4×8 (32 sq ft each) or 12 sheets of 4×12 (48 sq ft each).
Larger sheets always mean fewer sheets and fewer seams, which speeds up finishing and gives a flatter wall. The trade-off is weight: a 4×12 sheet of 1/2" drywall weighs around 65–70 pounds and usually needs two people or a panel lift to hang safely.
3 Ways to Use This Calculator
Budget a remodel
See the full material and labor cost before you start, so you can price a basement finish, a garage conversion, or a room addition and avoid mid-project surprises at the register.
Build a shopping list
Turn your room dimensions into exact quantities — sheets, screws, buckets of mud, rolls of tape, and corner bead — then export or print the list and take it straight to the store.
Compare sheet sizes
Use the what-if tool to test 4×8 against 4×12 sheets and different waste factors, and watch the sheet count, seams, and cost update instantly to find the most efficient plan.
Estimating Screws, Compound & Tape
Drywall screws
Budget about one screw per square foot — roughly 32 per 4×8 sheet on walls framed 16" on center, driven every 12" in the field and 8" at the edges. Ceilings and tighter spacing use more; 24" framing uses fewer. A 1 lb box holds about 320 screws.
Joint compound
One 4.5-gallon bucket of all-purpose compound finishes about 450 sq ft to a Level 4 finish — embedding the tape plus three coats. Divide your net area by 450 and round up, and keep a spare bucket so you never stall mid-coat.
Tape & corner bead
Plan for roughly half a lineal foot of tape per square foot of drywall to cover seams and inside corners; a 500 ft roll covers about 1,000 sq ft. Add corner bead for every outside 90-degree corner, sold in 8 ft sticks.
Waste Factor Explained
The waste factor is the extra material you buy beyond the exact net area to cover the realities of a job site: offcuts around windows and outlets, a sheet that cracks a corner during handling, and a spare panel for future repairs. For most rectangular residential rooms, 10% is the sweet spot. Add more — 12% to 15% — for rooms with many openings, angled or vaulted walls, closets, soffits, or if you are new to drywall and expect a few miscuts.
Buying too little almost guarantees a second trip to the store mid-project, while buying far too much wastes money on material you can't return once cut. The waste analysis above shows exactly how many extra square feet your chosen percentage adds.
Choosing the Right Drywall Type
Moisture-resistant vs standard
Standard white drywall is for dry living spaces. In bathrooms, laundry rooms, and kitchens, use moisture-resistant “green board” or a paperless mold-resistant board. Behind tile in showers and tub surrounds, step up to cement board or a fiberglass-faced backer, which won't break down when it gets wet.
Fire-rated (Type X)
Fire-rated 5/8" Type X drywall has a denser, glass-reinforced gypsum core that slows the spread of fire. Building codes require it on garage walls and ceilings that share a wall with the house, in stairwells, and on many multi-family party walls. It also resists sagging on ceilings and improves soundproofing.
Drywall Cost Factors
Installed drywall typically runs about $1.50 to $3.50 per square foot for materials and labor combined, or roughly $50 to $90 per sheet. Several factors move that number:
- Finish level — a Level 5 smooth finish for critical lighting costs more in labor and compound than a standard Level 4.
- Ceiling height and access — tall walls, stairwells, and cathedral ceilings need scaffolding and slow the crew down.
- Board type — 5/8" Type X, moisture- and mold-resistant, and soundproofing panels all cost more than standard 1/2" board.
- Region and demand — labor rates and material prices vary widely by market and time of year.
The Core Drywall Formulas
Wall area
Perimeter × wall height
Ceiling area
Length × width
Net area
Total surface − openings
Sheets
Net × (1 + waste %) ÷ sheet area
A 4×8 sheet covers 32 sq ft, a 4×10 covers 40, a 4×12 covers 48, a 4×14 covers 56, and a 4×16 covers 64. Round the final sheet count up to the next whole sheet.
Common Drywall Installation Mistakes
- 1
Forgetting the ceiling. It's easy to price the four walls and overlook the largest single surface in the room. Choose "Walls + Ceiling" or "Ceiling Only" so the overhead area is included and fastened correctly.
- 2
Mis-handling openings. Deduct large doors and windows, but don't over-deduct small ones — you still cut around them and generate offcuts. Many pros leave openings under about 10 sq ft in as built-in waste.
- 3
Skipping the waste factor. Buying the exact net area guarantees a second trip to the store. A 10% allowance covers cutting waste, a cracked corner, and a spare sheet for future repairs.
- 4
Using the wrong thickness. Half-inch board can sag on ceilings framed 24 inches on center, and standard drywall fails in wet areas. Step up to 5/8" or use moisture-resistant board where the job requires it.
- 5
Under-buying compound and screws. Running out of mud between coats stalls the job for a day of drying. Keep an extra bucket of compound and a spare box of screws on hand from the start.
Drywall quantities on this page use standard construction estimating practice — gypsum board coverage, a screw-per-square-foot fastener rate scaled to your framing, and a Level 4 compound coverage of roughly 450 sq ft per bucket. Results are educational planning estimates, not a construction bid; verify final quantities and local code requirements before purchasing. Last reviewed 2026-07-08. See our methodology and editorial standards.
Frequently Asked Questions
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