Drywall Mud Calculator

Multiply drywall area by the finish-level rate. Level 3 (texture-ready): 0.040 lb/sq ft. Level 4 (paint-ready, standard residential): 0.130 lb/sq ft. Level 5 (glossy/critical lighting): 0.180 lb/sq ft. For a 500 sq ft (46 m²) Level 4 job: 65 lb of mud, which is 5.4 gallons (about two 5-gallon buckets). The calculator above accepts either a direct area or full room dimensions and handles all the math.

Total mud weight (lb) = drywall area (sq ft) × finish-level rate (lb/sq ft). Convert to gallons by dividing by 12 (USG Sheetrock density). Bucket count = ceil(gallons ÷ bucket size). Example: 500 sq ft × 0.130 lb/sq ft = 65 lb → 65 ÷ 12 = 5.4 gal → ceil(5.4 ÷ 5) = 2 buckets of 5 gal. The rate already accounts for the multiple coats a Level 4 finish requires (typically three coats).

At Level 4 (paint-ready, most residential): 100 sq ft (9.3 m²) needs 13 lb / ~1 gallon — one 1-gallon bucket. At Level 3 (texture): 4 lb / 0.33 gallon — half a 1-gallon bucket. At Level 5 (glossy): 18 lb / 1.5 gallons — one 1.5-2 gallon bucket or part of a 5-gallon. The reference table on this page gives the full grid; multiply by your actual area.

All-purpose (the green-lid USG bucket): standard mud for tape, fill, and finish coats. Coverage 0.130 lb/sq ft Level 4. Lightweight (blue lid): 30% lighter, easier to sand, but slightly weaker — good for finish coats only, not first taping. Same coverage rate. Quick-set (powdered, mix on site): 20-90 minute working time, used for filling deep cracks and same-day repairs — buy by the bag, not the bucket. The calculator's rate works for all-purpose and lightweight equally.

Finish level sets the coverage rate. Level 3 uses 0.040 lb/sq ft — three coats over taped seams only, surface gets covered by texture or a thick paint. Level 4 uses 0.130 lb/sq ft — three coats over seams plus a wider feather, ready for standard paint. Level 5 uses 0.180 lb/sq ft — Level 4 plus a full skim coat over the entire wall, required for glossy paint and critical lighting. Going from Level 4 to Level 5 nearly doubles your mud cost.

Roughly 0.043 lb/sq ft per coat for Level 4 (three coats × 0.043 ≈ 0.130 lb/sq ft total). The first coat (tape coat) is thicker and goes on the seams only — about 0.060 lb/sq ft of seam length. Second coat (fill coat) widens the feather. Third coat (skim coat) is thin, just flattening the surface. For Level 5, add a fourth full-surface skim — that's where the extra 0.050 lb/sq ft comes from. The calculator gives the total — divide by 3 for a per-coat estimate.

Yes — buy one extra bucket beyond the calculated number. Mud is cheap (~$15-20 per 5-gallon bucket) and a partial bucket left over is more useful than running short mid-job. Mud also dries out and skins over once opened, so it's not worth saving partial buckets for projects months later. Add 10-15% to whatever the calculator says if you're a first-time DIYer — second coats often go heavier than they should until you get the feel.

Pre-mixed (ready-mix) all-purpose: comes in 1-gallon, 3.5-gallon, 4.5-gallon, and 5-gallon buckets, ready to use, slow-drying — the standard for residential. Powdered (setting-type, hot mud): comes in bags, mix with water on site, sets chemically in 20-90 minutes. Powdered is used for filling deep gaps, same-day repairs, and where you can't wait 24 hours between coats. The calculator's gallon output applies to pre-mixed; for powdered, weight is what matters and the same rate (0.130 lb/sq ft Level 4) holds.

Imperial SKUs: 1 gal (3.8 L / ~5 kg) for repairs, single small rooms, anchor holes; 3.5 gal (13 L / ~17 kg) for mid-size rooms; 4.5 gal (17 L / ~20 kg) standard contractor SKU at some retailers; 5 gal (19 L / ~25 kg) the contractor default — covers ~700-800 sq ft of Level 4 finish, about $15-20 each at big-box, lasts 6 months unopened. Metric SKUs sold in AU/UK/EU: 5 / 17 / 20 / 25 kg buckets — 20 kg is the contractor default. Switch the calculator to Metric in the unit selector to pick from kg buckets directly.

Yes — pick Metric in the unit selector at the top. Direct area input switches to m². Room dimensions input switches to meters. Mud weight outputs in kg (1 lb = 0.454 kg); gallons stay in gallons since joint compound is sold by the gallon globally (1 gal = 3.79 L). Coverage rates display per m² in the reference table. Common conversions: 500 sq ft = 46 m², 1 lb/sq ft = 4.88 kg/m². Your unit choice persists across pages via localStorage.