Fuse Bead Sizes and Pegboards Explained
Mini, midi and maxi beads look like one hobby, but they behave like three. Here is how bead size, pegboard size and finished size fit together — with the arithmetic to plan any project.
Updated 2026-10-23
Fuse beads — sold as Perler, Hama, Artkal and under many other names — are small plastic tubes that you place on a pegboard and melt together with an iron. The three common sizes are named mini, midi and maxi (also called jumbo or “biggie”). A pattern is just a grid of squares, so the size of the bead decides how big the finished piece is.
The three sizes
| Size | Nominal width | Beads per 10 cm | Typical use |
|---|---|---|---|
| Mini | about 2.5–2.6 mm | 38 | Detailed small pieces, jewellery, miniatures |
| Midi | 5 mm | 20 | The standard size: keychains, coasters, wall art |
| Maxi / jumbo | 10 mm | 10 | Young children, large simple shapes |
Midi is by far the most common size, and most online patterns assume it. The widths above are nominal: brands differ by a fraction of a millimetre, and ironing melts the beads together so the piece ends up slightly smaller or irregular. Use them for planning, not for precision engineering.
How pegboards work
A pegboard is a plastic sheet with pegs on a regular grid. The distance between pegs equals the bead width, which is why a board only works with its own bead size: midi beads on a midi board, mini beads on a mini board. Boards come in several shapes — squares, circles, hearts, hexagons — and sizes. The one most patterns use is the large square board with 29 × 29 pegs, which is 14.5 cm across with midi beads (29 × 5 mm).
The number of pegs is what matters for a pattern, not the outside dimension of the board. A pattern that is 29 beads wide and 29 beads high fits a 29 × 29 board exactly. Shaped boards have fewer usable pegs than their outer size suggests, so count pegs before you start.
Finished size, the arithmetic
- Width = beads across × bead width. 40 beads of 5 mm = 200 mm = 20 cm.
- Height = beads down × bead width.
- Beads needed = beads across × beads down, minus any empty squares.
- Boards = (beads across ÷ pegs per board, rounded up) × (beads down ÷ pegs per board, rounded up).
Example: a 58 × 40 design with midi beads is 29 × 20 cm. It needs 2,320 beads (fewer if parts are empty) and 4 boards of 29 × 29 (58 ÷ 29 = 2 across, 40 ÷ 29 = 1.4 rounded up to 2 down). The same grid in mini beads is only 15.1 × 10.4 cm; in maxi beads it is 58 × 40 cm. The bead calculator does these sums for you.
Designs larger than one board
Big designs are built in sections. Some boards are made to connect, so you can assemble a larger surface, place the beads across all of them and iron the whole piece in one go; with unconnected boards you iron each section separately and join the pieces afterwards, for example by gluing them to a backing. Check which approach your boards support before you plan, and mark the board borders on your pattern — the generator and maker have a Board size setting that draws heavy lines at every board edge.
Choosing a size for your project
| Project | Suggested size | Why |
|---|---|---|
| Keychain or magnet | Midi, 12–20 beads wide | Small, quick, strong enough when ironed on both sides |
| Coaster | Midi, about 20 × 20 beads | Roughly 10 cm; flat and heat-resistant if it is only for cold drinks |
| Portrait or pet | Midi, 58 × 58 or larger | Needs enough beads for faces |
| Miniature or earring | Mini | Small beads give fine detail but are fiddly |
| Group activity with young children | Maxi | Large beads are easier to pick up and place |
Mixing brands and sizes
Beads of the same nominal size from different makers usually fit the same boards, but small differences in diameter and melting temperature can show up in the ironed result. For a single piece, use one brand and one size throughout. Never mix sizes in one design: a mini bead placed on a midi board does not sit on the peg properly.
Perler, Hama and Artkal are trademarks of their owners. BeadPatternKit is independent and not affiliated with them.
Frequently asked questions
Which bead size is the standard?
Midi beads, 5 mm wide, are the standard size sold by most brands. Most patterns online assume them.
How big is a 29 × 29 pegboard?
With midi beads a 29 × 29 design measures about 14.5 × 14.5 cm, because 29 beads × 5 mm = 145 mm.
Can I use mini beads on a midi pegboard?
No. The peg spacing must match the bead width, so each bead size needs its own board.
Do different brands of midi beads fit the same boards?
Usually yes, but small differences in size and melting behaviour exist. Use one brand for one piece.