Understanding your result
The headline is the number of pieces to buy at the length you chose, and the line under it gives the linear feet split between corners and the shorter runs. The tiles separate the corner pieces from the pieces for returns and edges, and give the fasteners for the bead type.
Corners and short runs are counted differently on purpose. A vertical corner takes whole pieces, one per corner if the piece is at least as tall as the corner, two with a splice if not, because nobody splices a corner from offcuts. Returns around windows and doors and the edges of soffits are short runs that can be cut from pieces and offcuts, so they are counted by length with a waste allowance. That is why a 9 ft corner changes the order more than nine feet of soffit does.
The fixing line says how each type goes on. The compound for the bead is part of the finish, counted by the joint compound calculator; the inside corners are taped, counted by the tape calculator. If the outside edges come from a boxed duct, the soffit and bulkhead calculator gives the edge length for you.
How we calculate this
The edge per returned opening is the length of drywall edge that wraps into the jamb: both sides and the head of a window or door, and the sill too if the sill is drywalled. A 3 × 5 ft window returned on three sides is 5 + 5 + 3 = 13 ft. Openings with wood jambs and casing have no bead and are not counted.
Fastener spacing for metal bead follows common manufacturer guidance of a nail or screw every 8 to 9 in on each flange; vinyl bead is sprayed with adhesive and stapled every 6 to 8 in; paper-faced bead uses no fasteners and is bedded in compound. Bead sizes and lengths are on the standard sizes table.
The assumptions behind the numbers
| Assumption | Default | Where it comes from |
|---|---|---|
| Piece lengths | 8, 9 and 10 ft | Standard lengths (ClarkDietrich, Trim-Tex, USG catalogues) |
| Metal bead fasteners | Both flanges, every 9 in | Manufacturer installation guidance (8 to 9 in) |
| Vinyl bead fasteners | Staples every 6 to 8 in with spray adhesive | Vinyl bead makers’ instructions |
| Paper-faced bead | Bedded in compound, no fasteners | Manufacturer instructions |
| Edge per returned window | 13 ft | A 3 × 5 ft window returned on three sides |
| Waste on short runs | 10% | Our figure for miters and offcuts |
Assumptions last reviewed October 8, 2026.
The calculator does not count L-bead or J-bead (the trims used where drywall meets another material), shadow-line reveals, or the bullnose corner caps used with rounded bead. It assumes straight corners; arches take flexible bead, one of the options, with the curve measured along its edge. How bead fits into the passes of a finish is in the guide to the levels of finish, and why paper-faced bead and paper tape crack less is in the paper vs mesh tape guide.
Two worked examples
Six 9 ft corners and three returned openings, vinyl bead in 10 ft pieces
- Corners: 6 × ⌈9 ÷ 10⌉ = 6 pieces, no splices
- Returns: 3 openings × 14 ft = 42 ft; 42 ÷ 10 × 1.1 = 4.6, rounded up to 5 pieces
- 11 pieces of 10 ft vinyl bead, 96 ft in all, about 330 staples
With 8 ft pieces the six corners would need two pieces each, twelve pieces and six splices, for the sake of a foot of height. The 10 ft piece is the cheaper corner.
Two 8 ft corners and a 40 ft soffit, paper-faced bead
- Corners: 2 × ⌈8 ÷ 8⌉ = 2 pieces
- Soffit edges: 40 ÷ 8 × 1.1 = 5.5, rounded up to 6 pieces
- 8 pieces of 8 ft paper-faced bead, 56 ft, no fasteners; bedded in compound
A long soffit is a run of short pieces end to end; butt them tight and stagger nothing, since a soffit edge is one straight line. Paper-faced bead hides those butts better than metal.
Where to find your inputs
Outside corners. Count every vertical edge that points into the room: closet returns, chimney chases, boxed posts, the end of a half wall.
Height. The corner height, floor to ceiling, which may differ from the room height where a soffit drops the ceiling.
Returned openings. Windows and doors without wood trim, where the board turns into the opening; measure the edge length of one and count them.
Other edges. Soffits, bulkheads, beams, half-wall caps: measure each outside edge along its length.
Common mistakes
- Splicing corners from offcuts. Splices crack. Buy pieces long enough for each corner.
- Bead not tight to the board. A gap behind the flange becomes a crack when the corner is knocked. Fasten it tight and straight.
- Tape over metal bead. It blisters. Compound only over metal and vinyl flanges.
- Metal bead in a bathroom. It rusts through the paint. Vinyl or paper-faced.
- Bead on before the board is finished hanging. Hang everything, then bead, then tape.
- Not checking the bead is plumb. A bead that leans shows down the whole height of the corner.
Questions people ask
- How many pieces of corner bead do I need?
- One piece per outside corner, cut to the corner height, plus enough pieces for the window and door returns and soffit edges by their total length. A room with four 8 ft corners and two returned 3 × 5 ft windows needs 4 pieces for the corners and 4 more for the 26 ft of returns, 8 pieces of 8 ft.
- What length does corner bead come in?
- The common lengths are 8, 9 and 10 ft (2.44, 2.74 and 3.05 m). Buy the length that covers your corner height in one piece; a 9 ft ceiling wants 10 ft bead, not two 8 ft pieces spliced.
- Metal, vinyl or paper-faced corner bead?
- Metal bead is cheap and nailed or crimped on, but it dents and rusts in damp rooms. Vinyl bead is glued and stapled, does not rust and springs back from knocks. Paper-faced metal bead is set in compound like tape, does not crack along the flange and gives the best edge; most professional finishers use it.
- How do you fasten metal corner bead?
- With drywall nails or screws through both flanges every 8 to 9 in, or with a corner bead crimper that punches the flange into the board. The bead must be straight and tight to the board along its full length; any gap shows as a crack after painting.
- Does corner bead need tape?
- Metal and vinyl bead do not; the compound goes straight over the flanges. Paper-faced bead has its own paper and is bedded in compound like tape. Never put paper tape over metal bead; it blisters.
- How much compound does corner bead take?
- An outside corner gets three coats like a flat joint, each wider than the last, about 6 in on each side by the final coat. The manufacturer coverage per 1,000 sq ft of board used by the joint compound calculator already includes the beads of a typical room.