Free drywall calculator — the whole materials list, not just sheet count
Enter the room size, tell it whether you are covering walls, ceiling or both, and get sheets, joint compound, tape, screws and corner bead in one list. Openings come off the total. No signup, no email, nothing to download.
Most drywall calculators stop at sheets. The compound and tape are where people actually run short at 4pm on a Saturday, so this one figures those too and shows you the math behind each line.
How to use it
1. Enter length, width and ceiling height. Standard ceilings are 8 ft; the default is set there.
2. Pick what you are covering. Walls and ceiling for a new room; walls only for a ceiling that stays; ceiling only for a repair.
3. Count doors and windows. The calculator removes 21 sq ft per door and 15 sq ft per window — the standard estimator allowances.
4. Choose your sheet. 4 × 12 sheets mean fewer butt joints and less finishing on long walls, if you can get them into the room. ⅝" is for ceilings, garages and anywhere code calls for Type X.
5. Put in your prices. Defaults are rough national averages. Swap in your supplier's numbers and the total becomes something you can bid from.
How the math actually works
- Wall area — 2 × (length + width) × height. Ceiling is length × width.
- Openings — 21 sq ft per door, 15 per window. Small openings are usually cut out of a full sheet anyway, which is what the waste factor is for; don't subtract them twice.
- Sheets — net area × (1 + waste) ÷ sheet area, rounded up once at the end. Rounding up per wall is the classic way to buy three sheets you didn't need.
- Joint compound — 0.053 lb per sq ft of board for a three-coat finish (tape, fill, skim), at 61.7 lb per 4.5 gal bucket. Roughly one bucket per 1,150 sq ft.
- Tape — about 1 linear ft per sq ft of board, which covers flat joints plus inside corners. That is the standard estimator figure and it is generous on big open walls.
- Screws — 32 per 4 × 8 sheet on 16" centres, about 1 per sq ft. A 1 lb box of #6 × 1¼" holds roughly 300.
- Corner bead — only when you enter outside corners. Most rooms have none; bulkheads and closets do.
Worked example: a 12 × 14 bedroom
Twelve by fourteen, 8 ft ceiling, walls and ceiling, one door and one window, 4 × 8 sheets, 10% waste:
- Walls 416 sq ft + ceiling 168 sq ft − 36 sq ft of openings = 548 sq ft net
- 19 sheets of ½" 4 × 8
- 1 bucket of all-purpose compound (about 29 lb used)
- 2 rolls of paper tape
- 3 lb of screws (about 608)
At the default prices that is about $337 in materials, or $0.62 per sq ft. Hung, taped and finished by a pro, drywall usually lands between $1.50 and $3.00 per sq ft depending on the finish level and your market — labor is most of the job.
Turn it into a quote
Hit Copy list and paste it into an estimate. Then price the labor with the drywall pricing calculator, which works from your own hourly cost and production rate, and send it with the estimate generator. Wondering what drywall installers earn? See drywall installer salary by state.
FAQ
How many sheets of drywall do I need for a 12x12 room?
With 8 ft ceilings, a 12 × 12 room has 384 sq ft of wall and 144 sq ft of ceiling. After one door and one window, that is about 492 sq ft net, or 17 sheets of 4 × 8 with 10% waste for walls and ceiling — 14 sheets for walls only.
How much joint compound per sheet of drywall?
Figure about 1.7 lb of all-purpose compound per 4 × 8 sheet for a full three-coat finish, or 0.053 lb per sq ft. One 4.5 gal bucket (61.7 lb) does roughly 36 sheets. Topping and lightweight compounds cover a little differently, but not enough to change the bucket count on a normal room.
How much drywall tape do I need?
About 1 ft of tape per sq ft of board is the standard estimator figure, which covers the flat joints and inside corners. A 500 ft roll handles roughly 15 sheets of 4 × 8. Mesh tape comes in shorter rolls, so buy accordingly.
Should I use 4x8 or 4x12 drywall?
4 × 12 sheets cut the number of butt joints on long walls, and butt joints are the hardest to finish flat. Use them when the room, the stairwell and your helper can handle a 12 ft sheet. For ceilings, 4 × 12 run perpendicular to the joists is the pro default.
When do I need 5/8 inch drywall?
Most codes require ⅝-inch Type X on garage walls and ceilings shared with living space, and many builders use it on all ceilings because it sags less on 24-inch joist spacing. Check your local code before you buy — the calculator only changes the price, not the code.
How much waste should I allow for drywall?
10% is normal for a rectangular room. Go to 15% for rooms with lots of angles, closets or vaulted ceilings, and 5% for large open walls with few cuts. The calculator applies waste to the area before rounding to whole sheets.
Is this calculator free?
Yes, completely. No account, no email, no download. It runs in your browser and we never see your numbers.