Corner bead calculator
Corner bead goes on every outside corner: wall corners, bulkheads, and the edges of window and doorway returns that are wrapped in drywall. Count each run; each one gets whole pieces, because splicing bead mid-corner shows.
Enter your measurements
More options: Other
- Linear length of corners
- 0 ft
No outside corners or drywall-wrapped openings: no bead needed
- Most simple rectangular rooms need no corner bead: inside corners take paper tape. Count only corners that stick out into the room, and window or door openings finished in drywall instead of wood trim.
Bead for outside corners at this height
| Outside corners | Pieces to buy | Linear length of corners |
|---|---|---|
| 1 | 1 piece | 8 ft |
| 2 | 2 pieces | 16 ft |
| 4 | 4 pieces | 32 ft |
| 6 | 6 pieces | 48 ft |
| 8 | 8 pieces | 64 ft |
Bead is counted by the run, not by total length: a 9 ft wall corner needs a 9 ft or 10 ft piece, or two 8 ft pieces, never 1.1 of something. Openings get one piece up each side and one across the top. New to this? Drywall words explained.
How the corner bead count works
pieces per run = run length ÷ bead length, rounded up wall corners: corners × pieces per corner openings: openings × (2 × pieces per side + pieces across the top)
Standard lengths are 8, 9 and 10 ft; USG’s interior finishing catalog lists most of its metal and paper-faced corner beads in those lengths, a few also in 12 ft. Pick the length that covers your wall height in one piece: 8 ft bead for 8 ft walls, 9 or 10 ft for 9 ft walls.
Types of corner bead
- Bare metal bead is nailed, crimped or screwed through the board into the framing, then covered with compound.
- Paper-faced metal bead is bedded in joint compound like tape; its paper flanges bond with the mud and resist edge cracking.
- Bullnose beads give a rounded corner; offset and 135° beads suit angled walls and bay windows.
- Vinyl bead is common in damp areas and doesn’t rust.
Tips
- Check the corner is plumb before fixing the bead; the bead sets the line every coat of mud follows.
- Cut wall-corner bead about 1/2 in shorter than the wall height, as USG’s installation guide shows; the baseboard covers the bottom.
- USG’s estimate for joint compound already includes covering metal corner bead in a typical room, so you don’t need to add mud for it separately unless the room is all corners: see the joint compound calculator.
For the rest of the room’s drywall, see how many sheets of drywall for a 12x12 room and how much drywall tape per sheet.
What you’ll need
- Metal or paper-faced corner bead (8–10 ft)Budget price
Protects outside corners. Buy lengths that cover each corner in one piece where you can.
See options on Amazon (opens in a new tab) - Taping knife set (6, 10, 12 in)Budget price
Narrow for embedding tape and screw spots, wide for feathering the second and third coats.
See options on Amazon (opens in a new tab) - All-purpose joint compound (ready-mixed)Budget price
Tapes, fills and finishes. USG estimates about 10 gallons per 1,000 sq ft of panels for its All Purpose compound.
See options on Amazon (opens in a new tab) - Snap-off utility knife and bladesBudget price
Wallpaper and drywall both reward a fresh blade. Snap often.
See options on Amazon (opens in a new tab)
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Frequently asked questions
How much corner bead do I need?
Often none: simple rectangular rooms have only inside corners, which take tape. Otherwise, about one stick per outside corner if the bead is as long as the wall is high, plus two sticks or so for each drywall-wrapped window, since the short top piece usually comes out of a side’s offcut.
What lengths does corner bead come in?
Standard lengths are 8, 9 and 10 ft, according to USG’s finishing products catalog; some beads also come in 12 ft, and flexible tape-on bead in 100 ft rolls.
Do inside corners need corner bead?
No. Inside corners are finished with creased paper tape (or a paper-faced inside-corner bead); outside corners get bead.
How much corner bead for a window?
A window returned in drywall (no wood casing) takes a piece up each side and one across the top, plus one along the sill if that is drywall too. For a 3 × 5 ft window that is 13 ft of bead: two 8 ft sticks, since the top comes out of a side’s offcut.
Sources
- USG, Interior Finishing Products catalog (J1424) (opens in a new tab) — Paper joint tape in 75, 250 and 500 ft rolls; corner bead in standard 8, 9 and 10 ft lengths; ceiling spray texture in 32 and 40 lb bags.
- USG, How to Install and Finish Sheetrock Brand Gypsum Panels (J371) (opens in a new tab) — Panel coverage table; per 1,000 sq ft of panels: 2.7 lb of Type W screws (12 in on ceilings, 16 in on walls), 5.3 lb of nails, 370 ft of joint tape, about 10 gal of All Purpose or 9 gal of Plus 3 compound; First Coat primer at 400 sq ft/gal.