Drywall Calculator

Add the wall area (perimeter × height, minus doors and windows) and the ceiling, divide by the sheet size (32 sq ft for a 4×8), add 10% waste and round up. A 12×12 room with 8 ft ceilings needs 17 sheets of 4×8 for walls and ceiling, about 21.3 hours to hang and finish to Level 4, and prices at $1,681 on industry-default rates, $3.41 per square foot of board.

Updated 2026-10-21 · by Devon Davila, Founder, Krib · methodology and sources below

The interactive calculator on this page needs JavaScript. The method, constants and worked examples below are the same ones it uses.

What this calculates

Net board area from room dimensions with doors and windows deducted, with or without the ceiling. Sheets for the size you hang, with waste, rounded up. Joint compound, tape and screws from standard coverage, rounded to buckets, rolls and pounds. Hang hours per sheet and finish hours per sheet by Gypsum Association finish level. Then a price from burdened labor, materials, overhead, general and administrative cost and your target margin, with the price per square foot that drywall is usually quoted in.

Formula

wall_sqft      = 2 × (length + width) × height − doors × 20 − windows × 15
area           = Σ wall_sqft + Σ ceiling (length × width), if ceilings are included
sheets         = ceil( area ÷ sheet_sqft × (1 + waste) )   4×8 = 32, 4×10 = 40, 4×12 = 48
mud_lb         = area × 0.053   → buckets of 61.7 lb (4.5 gal), rounded up
tape_rolls     = ceil( area ÷ 500 )   500 ft rolls
screws         = area × 1   → lb at 300 per lb, rounded up
hang_hours     = sheets × 0.5 × (sheet_sqft ÷ 32)
finish_hours   = sheets × hours_per_sheet(level) × (sheet_sqft ÷ 32)
price          = (labor + materials + labor × overhead) × (1 + G&A) ÷ (1 − margin)   labor = hours × wage × (1 + burden)

Assumptions and sources

ConstantDefaultSourceAs of
Door and window deductions20 sq ft and 15 sq ftCommon estimating convention; drywall still goes above and beside openings, which is what the waste factor covers—
Waste10%Typical for rectangular rooms; 15% for rooms with angles, soffits or many openings—
Joint compound0.053 lb per sq ftUSG coverage guidance for three-coat taping with all-purpose compound (about 61.7 lb per 4.5-gal bucket)Oct 2026
Tape1 roll (500 ft) per 500 sq ftRule of thumb for 4×8 board with standard joint spacing—
Screws1 per sq ft, 300 per lb1-1/4" coarse-thread screws at 12" on ceilings and 16" on walls—
Hang labor0.5 h per 4×8 sheetResidential crew of two, measured, cut, screwed; scaled by sheet area for 4×10 and 4×12Oct 2026
Finish labor by levelL0 0 h · L1 0.2 h · L2 0.4 h · L3 0.6 h · L4 0.75 h · L5 1 hGypsum Association GA-214, Levels of Finish; hours per 4×8 sheet across tape, fill, skim and sandOct 2026
Material costssheet $14 (½") / $16 (⅝") per 4×8 · mud $18/bucket · tape $6/roll · screws $8/lbContractor-grade retail, Orange County, CAOct 2026
Wage · burden · overhead · G&A · margin$26/h · 22% · 25% of labor · 5% · 30%Krib seed rate card; drywall installers (BLS 47-2081) earn a similar medianOct 2026

Worked examples

One 12×12 room, 8 ft ceilings, walls and ceiling, Level 4

The default: one door, one window, ½" 4×8 board, 10% waste, finished for flat paint.

Walls, net of openings349 sq ft
Ceilings144 sq ft
Board area493 sq ft
Sheets, 4x817 (10% waste)
Joint compound26 lb · 1 bucket (4.5 gal)
Tape1 roll
Screws493 · 2 lb
Hang8.5 h
Finish to Level 412.8 h
Materials$278.00
Recommended price$1,680.84 (30% margin = 42.9% markup)
per sq ft of board$3.41

Open this example in the calculator

Garage, 20×22 with 9 ft walls, no ceiling, ⅝" 4×12, Level 2

Fire-rated ⅝" on the walls only, long sheets to cut joints, taped and one coat because it will not be painted to a finish.

Walls, net of openings706 sq ft
Ceilings—
Board area706 sq ft
Sheets, 4x1217 (10% waste)
Joint compound37 lb · 1 bucket (4.5 gal)
Tape2 rolls
Screws706 · 3 lb
Hang12.8 h
Finish to Level 210.2 h
Materials$462.00
Recommended price$2,057.95 (30% margin = 42.9% markup)
per sq ft of board$2.91

Open this example in the calculator

What changes the number

What drywall contractors charge

$1.50 – $3.50 per sq ft, hung and finished — residential, materials and labor, United States, 2026. Public sources, verified Oct 2026.

Public-source range. Level 4 finish in an accessible room sits in the middle; Level 5, ceilings and small jobs push to the top. The calculator's price per square foot should land inside this range on default rates.

Finish levels (GA-214) and what they cost in time

LevelWhat it meansFinish hours per 4×8 sheet
Level 0hung only, no taping0
Level 1tape set in compound (attics, above ceilings)0.2
Level 2tape plus one coat (garages, behind tile)0.4
Level 3two coats, heavy texture to follow0.6
Level 4three coats, standard for flat paint0.75
Level 5skim coat, gloss paint or critical light1

Hours cover taping, fill coats, skim where required and sanding; hanging is separate. Level 4 is the standard for flat or eggshell paint; Level 5 for gloss, dark colors or strong side light.

Questions painters ask

How many sheets of drywall do I need for a 12×12 room?

With 8 ft ceilings, one door and one window: about 350 square feet of wall plus 144 of ceiling, 493 square feet of board. In 4×8 sheets with 10% waste that is 17 sheets; walls only, 12. Change the sheet size or waste above and the count updates.

How do I calculate drywall for a whole house?

Add each room's wall area (perimeter times height, minus openings) and ceiling, then divide by the sheet size and add waste. Add every room in the calculator and it aggregates sheets, mud, tape and screws for a single material order.

Should I use 4×8 or 4×12 sheets?

4×12 sheets on walls over 12 ft long eliminate butt joints, which saves finishing time and makes a flatter wall. They need two people and clear access. 4×8 is the default for small rooms, stairs and anything you carry alone.

How much joint compound and tape per sheet?

About 1.7 lb of all-purpose compound and 16 ft of tape per 4×8 sheet for a Level 4 finish, which is 0.053 lb and one 500 ft roll per 500 square feet. A 4.5-gallon bucket covers roughly 36 sheets.

How long does it take to hang and finish drywall?

About half an hour per 4×8 sheet to hang and 0.75 hours per sheet to finish to Level 4 over several days of drying. A 12×12 room is a day to hang and finish for a crew of two, plus drying time between coats.

How much does drywall cost per square foot installed?

Public guides put hung and finished drywall at $1.50 to $3.50 per square foot in 2026, materials included. Level 5 finish, ceilings and small jobs run higher. The calculator shows your own price per square foot under the sheet count.

When do I need ⅝ inch drywall?

Ceilings with 24" joist spacing, garages and walls that need a fire rating (between a house and an attached garage, or between units). It costs about 15% more per sheet and weighs more to hang.

Can I turn this into a quote?

Yes. "Send this as a quote" opens a hang-and-finish line in Krib's quote builder at your price per square foot. Krib is free for contractors, with no monthly fee; add demolition, texture or paint lines and your customer accepts online.

Related

Turn this takeoff into a quote your customer can accept online

The hang-and-finish line opens in Krib's quote builder at your price per square foot. Free for contractors, no monthly fee.

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