Drywall Calculator
Calculate how much drywall you need — enter your room size and sheet size to get the number of sheets plus joint compound, tape and screws, with a waste allowance.
United States — national average · 2026 prices
Material only unless stated as installed. Excludes tax, permits and local labour. Verify with local suppliers — see how we calculate.
How this calculator works
Every figure above comes from the formula below, applied to the assumptions listed. Nothing is looked up from a hidden table — you can reproduce the result by hand.
Formula
wall area = 2 × (length + width) × ceiling height · ceiling area = length × width
total = (wall area + ceiling area if included) × (1 + waste ÷ 100)
sheets = total ÷ sheet area, rounded up (4×8 = 32 · 4×10 = 40 · 4×12 = 48 sq ft)
joint compound = total ÷ 125 sq ft per gallon · tape ≈ total × 0.6 ft · screws ≈ 1 per sq ft
Assumptions & limits
- Door and window openings are not subtracted. That is deliberate — sheets are cut around openings and the offcuts are usually unusable, so the gross area is the realistic purchase quantity.
- Joint compound is estimated at one gallon per 125 sq ft for a standard three-coat finish. A level 5 finish uses considerably more.
- Tape is estimated at 0.6 lineal feet per square foot of board and screws at about one per square foot, which reflects 16 in on-centre framing.
- Costs assume $15 per sheet, $16 per bucket of compound, $0.05 per foot of tape and $0.02 per screw.
- Default waste is 10%. Rooms with many openings, angles or short walls generate more offcut waste.
- Sheet size is a handling decision as much as a maths one: 4×12 sheets mean fewer seams to finish but are hard to carry and awkward in a stairwell.
- Not included: corner bead, furring, resilient channel, and the moisture- or fire-rated board that code requires in wet areas and on garage ceilings.
Worked example
A 14 × 12 ft room, 8 ft ceilings, ceiling included, 4×8 sheets, 10% waste
- Wall area = 2 × (14 + 12) × 8 = 416 sq ft · ceiling = 168 sq ft
- Total = (416 + 168) × 1.10 = 642 sq ft
- Sheets = 642 ÷ 32 = 20.1 → 21 sheets
- Compound = 642 ÷ 125 = 6 gal · tape = 642 × 0.6 = 386 ft · screws ≈ 643
Result:21 sheets plus finishing materials — about $406 to $564 in total.
Built and maintained by Christoph Ballmer, Honeygoat GmbH
Method and constants last checked against the calculator code on August 17, 2026. Independent trade review is not yet in place for this calculator — see how we handle review.
Read the site-wide calculation methodology · estimate vs. quote and safety limits
How many sheets of drywall do I need?
Add up the surface you are covering — the wall area (room perimeter × ceiling height) plus the ceiling if you are hanging it — subtract large openings like doors and big windows, add a waste allowance, then divide by the area of one sheet. The calculator above runs this for you and also estimates joint compound, tape and screws so you can build a full shopping list in one step.
sheets = (wall area + ceiling area − openings) × (1 + waste%) ÷ sheet area
A standard 4×8 ft sheet is 32 sq ft; a 4×12 ft sheet is 48 sq ft. Bigger sheets mean fewer joints to tape, but they are heavier and harder to handle alone. For everything else in the room, pair this with the paint calculator, the tile calculator and the flooring calculator.
Worked example: a 12 × 16 ft room with 9 ft ceilings
Say you are hanging drywall on the four walls and the ceiling of a 12 ft × 16 ft bedroom with 9-foot ceilings, and the room has one standard door and two windows. Here is the full count, step by step:
- Perimeter: (12 + 16) × 2 = 56 linear feet.
- Wall area: 56 ft × 9 ft = 504 sq ft.
- Ceiling area: 12 ft × 16 ft = 192 sq ft.
- Subtract openings: one door (about 21 sq ft) plus two windows (about 15 sq ft each, 30 sq ft total) = 51 sq ft removed.
- Net area: 504 + 192 − 51 = 645 sq ft.
- Add 10% waste: 645 × 1.10 = 710 sq ft to buy.
- Divide by sheet area (4×8 = 32 sq ft): 710 ÷ 32 = 22.2 → 23 sheets, always rounding up.
Using 4×12 sheets instead (48 sq ft): 710 ÷ 48 = 14.8 → 15 sheets. Fewer panels and far less taping, at the cost of a heavier lift. Many DIYers leave small openings in the area total and simply cut them out on site, which is the safer way to avoid coming up short.
Drywall thickness: which one to buy
Thickness changes the price, the weight and the fire and sag rating. Use this as a quick reference for a typical job — half-inch is the right default for most walls.
| Thickness | Where it is used | Notes |
|---|---|---|
| 1/2 in | Standard for most walls | The default choice; lightest version is easier to hang. |
| 5/8 in (Type X) | Ceilings, garages, fire-rated walls | Better sag resistance and fire protection; often required by code. |
| 3/8 in | Over existing surfaces, repairs | Used for going over old plaster or for a second layer. |
| 1/4 in | Curved walls, double-layer | Bends to a radius; usually doubled up for strength. |
Material and cost ranges
The table below shows typical 2026 US figures so you can sanity-check the calculator's output before you order. Material prices move with the lumber and gypsum market, and labor varies widely by region, so treat every dollar figure as a planning estimate.
| Item | Typical quantity / price (2026) |
|---|---|
| 4×8 sheet (1/2 in) | about $6–$8 each, weighs roughly 54 lb |
| 4×12 sheet (1/2 in) | about $10–$14 each, weighs roughly 82 lb |
| Joint compound (mud) | about 0.9 gallon per 100 sq ft for a 3-coat finish (USG) |
| Drywall tape | about 1 ft of tape per 2–3 sq ft of board |
| Drywall screws | about 32 screws per 4×8 sheet (roughly 1 per sq ft) |
| Installed cost (hang, tape, finish) | about $1.60–$3.75 per sq ft, Level 4 finish |
For the worked example above, 710 sq ft of board works out to roughly 6.4 gallons of joint compound, about 23 sheets of screws (≈740 screws, sold by the box), and an installed price in the rough range of $1,100–$2,700 if you hire it out — labor is 50–70% of a finished drywall bill.
How much waste should you add?
Waste covers offcuts, mistakes and damaged corners. The right allowance depends on how cut-up the room is.
| Room type | Suggested waste |
|---|---|
| Simple rectangular room, few openings | 10% |
| Bathroom or kitchen with cabinets and many cutouts | 15% |
| Complex layout, angled or sloped ceilings, lots of small walls | 20% |
Buying one or two spare sheets is cheap insurance against a second supply run, and a leftover sheet is handy for future repairs.
Fastening: screws and spacing
Following manufacturer and code spacing is what stops nail pops and sagging ceilings later. As a guide based on USG/IRC practice: on walls, space screws about 8 in apart along the panel edges and 16 in apart in the field; on ceilings, tighten that to about 7–8 in on the edges and 12 in in the field, because gravity pulls harder on overhead panels. That works out to roughly 32 screws on an average 4×8 wall sheet.
Common mistakes to avoid
- Forgetting the ceiling. If you are drywalling overhead, add it to the area — it is easy to size the order for walls only and come up short.
- Subtracting every small opening. Leaving small windows and outlets in the total gives you cutting material and a built-in safety margin; only subtract big openings like doors and patio sliders.
- Skipping the waste factor. Ordering the exact math with no allowance almost always means a second trip to the store mid-project.
- Using 1/2 in everywhere. Garages, attached-garage ceilings and other fire-rated assemblies often require 5/8 in Type X — check your local code before you buy.
- Hanging panels vertically by default. On walls, hanging sheets horizontally usually means fewer, lower seams that are easier to tape and finish.
When to hire a pro
Hanging a small, square room is a realistic weekend DIY job. Bring in a professional drywall crew when the job involves high or sloped ceilings, a fire-rated garage or party wall, a smooth Level 5 finish under raking light, or more board than you can hang and finish before the mud-and-sand work stretches across weeks. A two-person pro crew also handles heavy 4×12 sheets and overhead ceiling work far more safely than one person on a ladder. For a finished, paint-ready surface across a whole house, the labor is usually worth it — finishing quality is what shows once the walls are painted.
Figures here are planning estimates only and vary by region, supplier and market conditions in 2026. Quantities follow general manufacturer (USG/CertainTeed) and IRC guidance — verify thickness, fire rating and quantities with a local pro or supplier before you order.
Frequently asked questions
How many sheets of drywall do I need for a 12x16 room?
For a 12 ft by 16 ft room with 9-foot ceilings, hanging the walls and ceiling, you have about 504 sq ft of wall plus 192 sq ft of ceiling, minus roughly 51 sq ft for a door and two windows, for about 645 sq ft net. Add 10% waste (710 sq ft) and divide by 32 sq ft per 4x8 sheet, which is about 23 sheets — or about 15 sheets if you use larger 4x12 panels. Round up and add a spare for repairs.
How many screws do I need per sheet of drywall?
Plan on about 32 screws for a standard 4x8 sheet — roughly one screw per square foot. Following USG and IRC spacing, screws sit about 8 inches apart on the panel edges and 16 inches apart in the field on walls; on ceilings tighten the field spacing to about 12 inches because overhead panels carry more load. Screws are sold by the box, so estimate total board area and buy accordingly.
How much does it cost to install drywall per square foot?
In 2026 a fully installed Level 4 finish — hang, tape, mud and sand — typically runs about $1.60 to $3.75 per square foot in the US, with materials around $0.50–$0.75 and labor making up 50–70% of the bill. Coastal metro areas like New York, Boston, Seattle and San Francisco run higher, often $2.50–$4.00, while much of the Southeast and Midwest sits at $1.25–$1.75. These are estimates that vary by region and supplier.
Should drywall be hung horizontally or vertically?
On most walls, hanging sheets horizontally is the standard approach: it produces fewer seams, places the joints at a comfortable height to tape and finish, and ties more studs together for a flatter wall. Vertical hanging is used on tall walls and some commercial work. Either way, stagger the end joints so seams do not line up, and keep tapered edges together for the cleanest finish.
How many sheets of drywall do I need?
Add up the wall area (the room perimeter times the ceiling height) plus the ceiling if you are covering it, then divide by the area of one sheet — 32 square feet for a 4×8 sheet or 48 for a 4×12 — and add a waste allowance. The calculator above does this and also estimates mud, tape and screws.
How thick is drywall?
Standard wall drywall is 1/2 inch thick. Ceilings and garages or other fire-rated areas often use 5/8 inch (Type X) for extra sag resistance and fire protection, while 1/4 and 3/8 inch sheets are used for curved walls and for going over existing surfaces. Half-inch is the right default for most walls.
How much joint compound do I need?
As a rough guide, plan on about 1 gallon of ready-mix joint compound for every 100–150 square feet of drywall across taping and two or three finish coats. The calculator estimates the gallons from your total area; textured finishes use more.
What size sheets does drywall come in?
The most common sheet is 4×8 feet (32 sq ft); 4×12 (48 sq ft) is used on larger walls and ceilings to cut down on seams, and 4×9 and 4×10 are also available. Bigger sheets mean less taping but are heavier to handle. Pick your sheet size above.
How much drywall do I need for a 3,000 sq ft house?
As a whole-house rule of thumb, total drywall area runs about 3.5-4 times the floor area once every wall and ceiling is counted - so a 3,000 sq ft house needs roughly 10,500-12,000 sq ft of board, or about 330-375 of the 4x8 sheets. Treat that as an order-of-magnitude figure for pricing, since layout, ceiling height and openings swing it. For a real order, run each room through the calculator above and add the counts.