Drywall Calculator
Count the sheets, screws, tape and mud needed to board a room.
What you'll need to order
- 1/2 in drywall sheets
- drywall screws
- paper joint tape
- all-purpose joint compound
- corner bead
Prices vary by region and haul distance. Get quotes from at least two local suppliers.
How this calculator works
sheets = (wall area + ceiling area) ÷ 32 × 1.10
A 4 by 8 sheet covers 32 sq ft. Twelve-foot sheets cover 48 sq ft and produce far fewer butt joints, which are the hardest joints to finish invisibly — worth it if you can get them into the room.
Switch the site to metric — the control is in the footer — and your inputs, your results and the tables below follow. The formula, the constants, the guidance text and the sources stay in US units on purpose: that is how the standards they come from are written, and restating them would detach each figure from the document you are meant to be able to check it against.
Where these numbers come from
- ASTM C1396/C1396M (Gypsum Board) 2022 — standard gypsum panel dimensions, from which 32 sq ft per 4×8 sheet follows
The edition matters as much as the number. Jurisdictions adopt code revisions on their own schedule, so verify which one applies where you are building.
Worked example
With room length 14 ft, room width 12 ft, ceiling height 8 ft, openings to deduct 0 sq ft, this calculator returns 20.08 .
Waste allowance
The headline figure includes a 10% allowance for waste and over-ordering. The exact requirement is shown alongside it.
Drywall sheets by room size
Figures below assume room width 12 ft × ceiling height 8 ft × openings to deduct 0 sq ft. Open any row to load it into the calculator above — the link carries the numbers with it, so it can go straight to a supplier or a crew.
| Room length | Sheets needed (4x8) | Joint compound (gal) | Joint tape (ft) |
|---|---|---|---|
| 10 ft | 16.23 | 2.35 | 649.0 |
| 12 ft | 18.15 | 2.63 | 726.0 |
| 14 ft | 20.08 | 2.91 | 803.0 |
| 16 ft | 22.00 | 3.19 | 880.0 |
| 20 ft | 25.85 | 3.75 | 1,034 |
| 24 ft | 29.70 | 4.31 | 1,188 |
Rooms 12 ft wide with 8 ft ceilings, walls and ceiling, including a 10% waste allowance. Standard 4x8 ft sheets.
How much drywall for a room, basement or garage?
Open any row to load it into the calculator above — the link carries the numbers with it, so it can go straight to a supplier or a crew.
| Job | Size | Sheets needed (4x8) | Material cost |
|---|---|---|---|
| Small bathroom | 8 ft × 6 ft × 8 ft × 20 sq ft | 8.66 | $121 – $225 |
| Bedroom | 12 ft × 11 ft × 8 ft × 35 sq ft | 15.98 | $224 – $416 |
| Living room | 18 ft × 14 ft × 9 ft × 60 sq ft | 26.40 | $370 – $686 |
| Two-car garage | 24 ft × 24 ft × 9 ft × 150 sq ft | 44.34 | $621 – $1,153 |
| Basement finish | 40 ft × 25 ft × 8 ft × 80 sq ft | 67.38 | $943 – $1,752 |
Openings are the total square footage of doors and windows. Deduct them only when they are large — subtracting a single window rarely changes the sheet count.
Cost range uses $14–$26 per sheet for material only.
What does drywall cost per sheet?
Material typically runs $14 to $26 per sheet. Material only. Hung, taped and finished by a contractor runs $2 to $4 per square foot of surface, which is where most of the cost sits.
What moves the price:
- Thickness and type — moisture-resistant and Type X fire-rated cost more
- Sheet length: 12 ft sheets cost more but leave fewer joints to finish
- Level of finish, from Level 3 for textured walls to Level 5 under gloss paint
- Ceiling work, which is slower and priced higher than walls
Prices are US averages and move with fuel, season and haul distance. Always get two local quotes before budgeting.
Drywall types and where each belongs
| Type | Thickness (in) | Notes |
|---|---|---|
| Standard 1/2 in | 0.50 | Walls on 16 in centres; the default |
| Standard 5/8 in | 0.63 | Ceilings, and walls on 24 in centres |
| Type X fire-rated 5/8 in | 0.63 | Required on garage ceilings under living space |
| Moisture-resistant 1/2 in | 0.50 | Bathrooms outside the shower area |
| Cement board 1/2 in | 0.50 | Behind tile in wet areas; not drywall |
| Flexible 1/4 in | 0.25 | Curved walls, doubled up |
Use 5/8 in on ceilings regardless of code. Half-inch board sags between joists over time, especially once insulation above it gets damp.
Frequently asked questions
How many sheets of drywall do I need?
Work out total wall and ceiling area, divide by 32 for 4x8 ft sheets, then add 10%. A 12 by 14 ft room with 8 ft ceilings needs about 20 sheets.
How much drywall mud do I need per sheet?
Roughly 0.4 gallons of all-purpose compound per 4x8 sheet across all coats, and about 40 linear feet of tape. A five-gallon bucket covers 12 to 14 sheets.
How much does it cost to drywall a room?
A 12 by 14 ft bedroom takes about 20 sheets, so $280 to $520 in materials. Hung and finished by a contractor, expect $1,500 to $2,500 for the same room.
How many sheets of drywall do I need for a 12x14 room?
About 20 sheets of 4 by 8, covering walls and ceiling with 10% waste. Subtracting doors and windows saves a sheet or two, but the offcuts are useful so many hangers do not bother.
How much joint compound per sheet of drywall?
Roughly 0.145 gallons per sheet across three coats, so a 20 sheet room takes about 3 gallons. Buy the 4.5 gallon bucket for anything over 15 sheets.
Should I use 1/2 inch or 5/8 inch drywall?
Half inch for walls and for ceilings framed at 16 inch centres. Five-eighths for ceilings at 24 inch centres, where it resists sagging, and wherever fire rating is required such as a garage ceiling.
Should drywall be hung horizontally or vertically?
Horizontally on walls in residential work. It puts the butt joints at a comfortable working height, reduces total joint length, and ties more studs together. Vertical hanging suits commercial walls over 9 ft.