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Drywall Mud Calculator

Calculate how much joint compound you need for taping and finishing drywall.

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Joint compound needed gallons
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Joint compound, commonly called drywall mud, is used to embed tape over seams, fill screw holes, and create a smooth surface ready for paint. The amount you need depends on the total area of drywall and the finish level you are targeting. This calculator covers standard taping through full skim coating. Drywall finishing is rated on a scale from Level 0 to Level 5. Level 3 is the minimum for most residential walls that will be textured. It includes tape embedded in one coat of compound plus two additional coats over the tape and one coat over fastener heads. Level 4 is the standard for smooth painted walls and adds an extra skim coat over the joints. Level 5 is a full skim coat over the entire surface and is used for areas with critical lighting like long hallways or rooms with large windows that throw light at a low angle across the walls. A standard 4.5-gallon bucket of premixed all-purpose joint compound covers roughly 65 to 85 square feet at Level 4 finish, depending on your technique and how cleanly you tape. Experienced tapers waste less because their coats are thinner and more even. First-timers typically use 15 to 20 percent more material than the estimated amount. For a typical 12x12 room with 8-foot ceilings and one door, the total wall and ceiling area is roughly 528 square feet. At Level 4 finish, plan on about 37 gallons of joint compound, which is roughly 8 to 9 standard buckets. That sounds like a lot, but remember you are applying three separate coats over every joint, corner, and screw head in the room. Joint compound comes in premixed and setting-type (hot mud) varieties. Premixed is easier to work with and the right choice for most DIY projects. Setting-type compound hardens by chemical reaction rather than drying, making it better for deep fills and first coats where you need to recoat quickly. Many professionals use setting compound for the tape coat and premixed for the finish coats. Buy extra and do not worry about waste. Premixed compound keeps for months in a sealed bucket and is inexpensive compared to the labor of a second trip to the store. Running out mid-wall means visible lines where you stopped and restarted.