Counting sheets is the easy half. What costs you a weekend is joint length — and sheet size and direction change it more than anything else.
Openings are deducted at half. A door still needs board cut around it and the offcut is rarely reusable, so full deduction always leaves you short.
Doors figured at 21 sq ft, windows at 12 sq ft, both deducted at 50%.
Nine-foot ceilings are everywhere in houses built since the nineties, and standard 48″ board does not fit them. Two courses give 8 ft and leave a 12″ strip along the top, which means ripping a filler and finishing a butt joint the whole length of every wall.
Fifty-four inch board exists precisely for this. Two courses stack to exactly 9 ft with no filler strip and no long horizontal butt seam across every wall. It is stocked by most suppliers, costs a little more per sheet and less per square foot, and it removes the hardest part of the job.
Switch the sheet width above and watch the filler strip and its seam disappear. End seams where one sheet meets the next still exist — longer sheets are what reduce those.
Sheets are cheap and fast. Joints are slow. Every linear foot of joint needs tape, three coats of compound with drying time between them, and sanding.
There are two kinds and they are not equal. A tapered joint is the factory edge — the board is thinner there, so the compound sits in a recess and finishes flat easily. A butt joint is a cut end against a cut end with no recess, so the compound has to be feathered wide on both sides to hide a hump. Butt joints take roughly three times the work of a tapered joint of the same length.
Longer sheets and the right width are how you get rid of butt joints.
Horizontal, in nearly all residential work. It puts the tapered edge at working height, keeps total joint length down on a standard-height wall, and runs joints across the framing rather than along it so a bowed stud is less visible.
Vertical hanging belongs on tall commercial walls, and where a fire-rated assembly specifies it.
Plan on about 0.053 lb of compound per square foot of board across all coats — a 4.5 gallon bucket covers roughly 1,000 sq ft. Texture uses more, and a level 5 skim coat can double it.
Tape runs the full length of every joint plus every inside corner. Paper tape is stronger and the standard for flat joints and corners; mesh is faster but needs setting compound over it, not all-purpose.
About 32 on a 4×8 at 16″ o.c. — roughly 8″ in the field and 12″ on edges.
Half inch is standard on walls at 16″ o.c. Five eighths is required on ceilings at 24″ o.c. to stop sag, and in most fire-rated assemblies.
Because you still cut board around the opening and the offcut is usually scrap. Full deduction reliably leaves you a sheet short.