FREE DRYWALL & PAINT CALCULATOR
Drywall and paint calculator — sheets, mud, tape, and gallons for the room.
Enter the room, subtract the openings, and get board counts for 4x8 or 4x12 sheets plus compound, tape, primer, and two-coat paint quantities. Free, no signup.
Room inputs
| Surface area (openings deducted) | – |
| Drywall sheets (+10% waste) | – |
| Joint compound (4.5-gal buckets) | – |
| Joint tape (500 ft rolls) | – |
| Primer (gal, 1 coat @ 300 sq ft) | – |
| Paint (gal, 2 coats @ 350 sq ft) | – |
Estimates only. Deductions: 21 sq ft per door, 15 sq ft per window. Finish level, texture, and ceiling paint change quantities — verify against the actual scope.
Board math that matches how you buy
Wall area is perimeter × height; the ceiling adds length × width. Doors give back about 21 sq ft and windows about 15 — but hangers still order 10 percent over, because board breaks around openings rarely fall on a sheet edge. Fewer, bigger sheets cut finishing labor: every joint you don't create is three coats you don't run.
Calculating quantities is step one. Pricing the whole job is the hard part.
FieldSquire turns a walkthrough — voice notes, photos, measurements — into an editable, line-item estimate with your own labor rates and markup, then sends a branded PDF for signature. Solo plan free for 14 days, no credit card.
Start the free Solo trialFrequently asked questions
How many sheets of drywall do I need for a 12x12 room?
A 12 by 12 room with 8-foot ceilings has about 384 sq ft of wall, or 480 sq ft including the ceiling. That is roughly 16 sheets of 4x8 for walls and ceiling before openings, plus 10 percent waste. Enter your exact room above.
Should I use 4x8 or 4x12 drywall sheets?
4x12 sheets mean fewer joints to finish — a real labor saving on long walls and ceilings — but they are heavy and awkward in occupied houses and tight stairs. Crews default to 4x8 for service work and 4x12 where access allows.
How much joint compound per sheet of drywall?
Plan on about one 4.5-gallon bucket of ready-mix per 450–500 sq ft of board for a standard three-coat finish. Texture is extra. The calculator scales this from your board area.
How much paint do I need per square foot?
One gallon covers roughly 350 sq ft per coat on smooth, primed drywall. Two coats over fresh board is standard; new drywall also needs a primer coat at about 300 sq ft per gallon.
Can this build the whole drywall bid?
It returns material quantities. To price hanging, finishing levels, texture, and paint labor as separate reviewable lines, try the FieldSquire drywall estimating app free for 14 days.