How to calculate it yourself
Mud (gallons) = drywall area in ft² × 0.053. Tape (linear feet) = drywall area × 2.5. Round up to whole 4.5-gallon buckets (or 1-gallon containers for small jobs). Add 10% if you are a beginner — the first wall always wastes more than the math says.
Common scenarios
Bedroom with one wall to repair (10 ft²)
Buy a 1-quart container of pre-mixed all-purpose ($6-9) plus a 25-ft roll of paper tape ($3). Total: $10-12. Skip the bucket for repairs — it dries out faster than you can use it.
Standard 12×14 bedroom remodel
5 buckets of 4.5-gal lightweight all-purpose ($60-90) plus a 250-ft roll of paper tape ($5-8). Total: $65-100 in mud + tape. Add corner bead ($3-5 per 8-ft length) for outside corners.
Whole-basement finish (1,200 ft²)
31 buckets is heavy — for jobs this size pros usually mix their own mud with bagged powder ($10-15 per 25-lb bag, yielding ~3 gallons each). Saves $300-500 vs pre-mixed buckets, but you need a paddle mixer and a 5-gal pail to mix in.