Drywall finishing materials scale with the area of board hung. USG, the largest U.S. gypsum maker, publishes rates per 1,000 ft² of panels for a standard three-coat finish: about 10 gallons (138 lb) of ready-mixed all-purpose joint compound, 370 ft of paper tape and 2.7 lb of screws. This drywall mud calculator works out your drywall area from the room size, applies those rates with a waste allowance and rounds to pails, rolls and bags.
Haven't hung the board yet? Count sheets first with the drywall calculator. After finishing, the paint calculator sizes primer and paint.
How to use the drywall mud & tape calculator
- Enter the room length, width and wall height, and whether the ceiling is drywalled too.
- Subtract the area of doors and windows. A standard door is about 20 ft² and a 3 × 5 ft window 15 ft².
- Choose the joint compound. Many finishers use setting-type powder for the tape coat and ready-mixed all-purpose or lightweight for the finish coats; pick the one you will use most.
- Keep about 10% extra for corners, patches and sanding loss.
Formula
Rates per 1,000 ft²: all-purpose ready-mix 10 gal (≈138 lb); lightweight ready-mix 9 gal; setting-type powder 72 lb; drying-type powder 83 lb; tape 370 ft; screws 2.7 lb; primer 2.5 gal (400 ft² per gallon).
Worked example
A 12 × 12 ft bedroom with 8 ft walls and a drywall ceiling, one door and one window (35 ft²), finished with ready-mixed all-purpose compound and 10% extra.
- Drywall: 2 × (12 + 12) × 8 = 384 ft² of walls + 144 ft² of ceiling − 35 ft² = 493 ft².
- With 10%: 542 ft², or 0.542 thousand ft².
- Mud: 0.542 × 10 = 5.4 gallons (about 75 lb), so two 4.5 gallon pails.
- Tape: 0.542 × 370 = 201 ft, one 250 ft roll. Screws: 1.5 lb. Primer: 493 ÷ 400 = 1.2 gallons.
Mud and tape for common rooms
8 ft walls plus ceiling, no openings deducted, no waste.
| Room (8 ft walls + ceiling) | Drywall ft² | All-purpose mud | Lightweight mud | Tape |
|---|---|---|---|---|
| 10 × 10 ft | 420 | 4.2 gal | 3.8 gal | 155 ft |
| 12 × 12 ft | 528 | 5.3 gal | 4.8 gal | 195 ft |
| 12 × 16 ft | 640 | 6.4 gal | 5.8 gal | 237 ft |
| 14 × 20 ft | 824 | 8.2 gal | 7.4 gal | 305 ft |
| 20 × 24 ft | 1,184 | 11.8 gal | 10.7 gal | 438 ft |
Manufacturer rates per 1,000 ft²
| Product (per 1,000 ft² of drywall) | Quantity |
|---|---|
| Ready-mixed all-purpose compound | 10 gal (≈138 lb) |
| Lightweight all-purpose compound | 9 gal |
| Setting-type (hardening) powder | 72 lb |
| Drying-type powder | 83 lb |
| Paper joint tape | 370 ft |
| Type W drywall screws | 2.7 lb |
| Drywall primer | 2.5 gal |
These are averages for a standard Level 4 finish with three coats on flat joints and two on corners. A Level 5 finish adds a skim coat over the whole surface and uses considerably more compound. Textured ceilings also use more.
Which compound for which coat
Setting-type compound (hot mud) hardens by chemical reaction in a set time, such as 20, 45 or 90 minutes, so it's strong and lets you recoat the same day; it's popular for embedding tape and filling gaps. Ready-mixed all-purpose compound dries by evaporation and suits every coat. Lightweight compound is easier to sand and is usually used for topping coats. Behind the wall, the wall framing calculator counts studs, and the insulation r-value calculator sizes batts or blown insulation before you close it up.
Caveats and assumptions
- Rates are manufacturer averages. Wide gaps, poor board layout and many inside corners use more compound.
- Pail sizes vary (3.5 and 4.5 gallon are both common); adjust the count for what your store sells.
- Mesh tape is used with setting-type compound; paper tape works with all types. Follow the compound's directions.
- Screws assume typical 16 in framing and standard fastener spacing.
Frequently asked questions
How much drywall mud do I need per square foot?
About 0.01 gallon (1.3 fluid ounces, or 0.14 lb) of ready-mixed all-purpose compound per ft² of drywall, or 10 gallons per 1,000 ft².
How much joint compound for a 12x12 room?
With 8 ft walls and a ceiling, about 528 ft² of drywall, which needs roughly 5.3 gallons of all-purpose compound before waste, so two 4.5 gallon pails.
How much drywall tape do I need?
About 370 ft per 1,000 ft² of drywall, or 37 ft per 100 ft². A 4 × 8 sheet (32 ft²) uses about 12 ft of tape.
How many sheets of drywall does a bucket of mud cover?
A 4.5 gallon pail of all-purpose compound finishes about 450 ft², or roughly 14 sheets of 4 × 8 drywall.
How many screws per sheet of drywall?
Commonly about 28 to 32 screws for a 4 × 8 sheet on walls at 16 inch framing. By weight, USG lists about 2.7 lb of Type W screws per 1,000 ft² of drywall.
Sources
- USG — Sheetrock Brand Installation and Finishing Guide (J371) — compound, tape, fastener and primer quantities per area
- USG — Gypsum Construction Handbook — joint compound by weight per 1,000 ft² (ready-mixed, drying and setting powders)
- USG — Sheetrock Paper Joint Tape submittal sheet — tape coverage and roll lengths
This calculator gives estimates for planning and education. Check measurements, local codes, supplier specs and your school's official policy before relying on a result. See our disclaimer and how we build and check calculators.