For 1,000 square feet of drywall you need about 10 gallons of USG Sheetrock All Purpose joint compound, 11 gallons with 10% waste: three 4.5 gallon pails, plus 370 feet of paper tape. That covers the three coats of a Level 4 finish; the lightweight Plus 3 takes 9.4 gallons and Easy Sand setting compound about 52 pounds per 1,000 sq ft.
How the drywall mud calculator works
USG publishes the coverage of each Sheetrock compound per 1,000 square feet of board, for the usual system of a tape coat, a fill coat and a finish coat. The calculator scales that figure to your area, adjusts it for the finish level, adds waste and rounds up to whole packages.
Compound = board area ÷ 1,000 × coverage × (coats ÷ 3) × (1 + waste), then ÷ package size, rounded up
Tape follows the same logic: USG's paper tape submittals give about 370 ft per 1,000 sq ft of board.
Worked example: 1,000 sq ft, All Purpose, Level 4
- 1,000 ÷ 1,000 × 10 gal = 10 gal for three coats
- With 10% waste: 11 gal
- 11 ÷ 4.5 gal pails = 2.4, so 3 pails (or 11 ÷ 3.5 = 3.1, so 4 boxes)
- Tape: 1,000 ÷ 1,000 × 370 = 370 ft, two 250 ft rolls
How much joint compound do I need
Joint compound comes down to one rule: about 10 gallons of ready-mixed All Purpose per 1,000 sq ft of board for a full Level 4 finish, which is 0.32 gallons per 4 × 8 ft sheet (USG J1969). The "Joint compound needed" line under the result gives your figure in gallons or pounds, and in litres or kilograms in metric. This joint compound calculator adds 10% for waste and rounds up to whole pails. For All Purpose at Level 4:
| Sheets hung (4 × 8 ft) | Board area | Compound with 10% waste | 4.5 gal pails |
|---|---|---|---|
| 10 | 320 sq ft | 3.5 gal | 1 |
| 20 | 640 sq ft | 7.0 gal | 2 |
| 30 | 960 sq ft | 10.6 gal | 3 |
| 50 | 1,600 sq ft | 17.6 gal | 4 |
| 100 | 3,200 sq ft | 35.2 gal | 8 |
Lower finish levels take a fraction of that, since each joint coat counts one third of the system: Level 3 is two thirds and Level 2 one third. Setting compound is bought by weight, at about 52 lb per 1,000 sq ft.
Coverage by compound
| USG Sheetrock product | Coverage per 1,000 sq ft | Sold as |
|---|---|---|
| All Purpose, ready-mixed (green lid) | about 10 gal | 4.5 gal pail, 3.5 gal box |
| Plus 3, lightweight (blue lid) | about 9.4 gal | 3.5 gal box, 4.5 gal pail |
| All Purpose Midweight | about 9.4 gal | 4.5 gal pail, 3.5 gal box |
| Easy Sand, setting type powder | about 52 lb | 18 lb bag |
The figures come from USG's submittal sheets J1969, J498A, J963 and J621. Per 4 × 8 sheet (32 sq ft) that is 0.32 gallons of All Purpose or 1.7 pounds of Easy Sand powder.
Sheetrock mud calculator by sheet count
If you know how many sheets went up, switch to "Sheet count". Thirty 4 × 8 sheets are 960 sq ft of board: 9.0 gallons of Plus 3, 9.9 gallons with waste, so 3 boxes of 3.5 gallons. The drywall calculator gives the sheet count from room sizes and carries the same mud figure.
Levels of finish and how many coats
The Gypsum Association's GA-214 defines six finish levels. The calculator sizes the compound by the joint coats each one calls for:
| Level | What it is | Coats over tape | Where |
|---|---|---|---|
| 1 | Tape set in compound | tape only | attics, above ceilings |
| 2 | Tape embedded and wiped, thin coat | 1 | behind tile, garages |
| 3 | One more coat on joints | 2 | under medium or heavy texture |
| 4 | Two more coats on joints | 3 | flat paint, light texture |
| 5 | Level 4 plus a skim coat over everything | 3 + skim | gloss or dark paint, raking light |
USG's coverage figures describe the three-coat system, so Level 4 uses them as published, Level 3 takes two thirds and Levels 1 and 2 one third. That share is our assumption: each coat counts equal. At Level 3, 1,000 sq ft needs about 6.7 gallons before waste.
GA-216 gives the widths: the second coat reaches about 3½ in each side of the joint center and the third about 6 in, so a finished joint is about a foot wide. Fastener heads get three coats. The drawing next to the result shows these coats over the tape.
Level 5 adds a thin skim coat over the entire surface. USG publishes no skim coverage for these compounds, so the calculator asks for a rate: take it from your product label or your finisher. USG also says not to skim coat with setting-type compound.
All purpose, lightweight or setting type?
The ready-mixed compounds come wet in pails and boxes and dry by evaporation, so each coat waits for the last one to dry. Plus 3 weighs 25% less than conventional compound, according to USG. Easy Sand is a powder you mix with water that hardens by chemical set; USG sells it as Easy Sand 5, 20, 45, 90 and 210 in 18 lb bags and gives about 5 to 6 quarts of water per bag. Because it sets rather than dries, it suits a tape coat or deep fills you want to cover the same day, mixed in batches you can use before it sets. USG says not to use it for skim coats.
Tape rolls
USG sells paper tape in 75 ft rolls for patching, 250 ft rolls for hand taping and 500 ft rolls for taping machines. Pick the roll length and the calculator rounds up.
Next steps
Get the sheet count, screws and corner bead with the drywall calculator, compare the price of doing it yourself with the drywall installation cost calculator, and once the mud is sanded, work out primer and topcoat with the paint calculator. Patching a few holes instead? The drywall repair cost calculator prices that. All wall and ceiling tools are in drywall, paint and walls.