Sticker, card, keyfob or disc: which form factor?
The object decides. A sticker for a flat surface that will not be handled, a card for something carried and presented, a keyfob or disc for anything that takes abuse. Room matters more than looks, because the antenna fills the tag and the antenna is what sets the read distance.
The four common shapes
| Shape | Strength | Weakness | Belongs on |
|---|---|---|---|
| Sticker or label | Cheapest, thinnest, printable | Fragile once handled, adhesive dependent | Flat surfaces, posters, equipment |
| Card | Largest antenna you can pocket | Rigid, needs a wallet or holder | Business cards, access badges |
| Keyfob | Rugged, holed, hard to lose | Small antenna, short range | Keyrings, tool identification |
| Disc or token | Sealed, often screw fixed | Thicker, visually obvious | Machinery, outdoor points |
Two more appear often enough to name. An inlay is the bare tag before it is encased, sold for embedding into another product. An on metal tag is any of the above built with an isolating layer so it survives a conductive surface.
What decides between them
What the tag is attached to comes first. A flat clean surface takes a sticker, a curved or textured one usually does not, and metal takes only a tag built for it.
Whether it is handled comes second. Anything touched daily wears at the edges and lifts at the corners, which rules out a paper label regardless of how well it reads.
Whether it is carried comes third. A card lives in a wallet, a keyfob on a keyring, and a sticker on neither.
Why room beats preference
The antenna is a coil that occupies nearly the whole tag, so the outline you choose is close to the antenna you get. A card sized tag reads at a distance a small round sticker cannot approach.
That makes the size question a functional one rather than an aesthetic one. Choosing a small elegant tag for a public installation means choosing a tag people have to touch precisely, and a proportion of them will not.
Take the largest the object comfortably allows. Range gained this way costs nothing once the object is fixed.
The usual mistake
Choosing the shape from a catalogue photograph and discovering the surface afterwards.
The order that works is the reverse: identify the surface, the handling and the space, then pick the shape that survives all three. The catalogue is where you finish, not where you start.
The second mistake is buying one form factor for a deployment that has three kinds of location. A poster, a machine housing and a reception desk are different problems, and one tag rarely solves all of them well.
Frequently asked questions
Does the form factor change compatibility?
No. Compatibility follows the NFC Forum tag type, which is a property of the chip. The same chip appears in stickers, cards and keyfobs.
Which form factor reads furthest?
The card, among the pocketable shapes, because it holds the largest antenna. A large industrial disc can beat it, and neither is limited by the chip.
Can I embed a tag inside my own product?
That is what inlays are for. They are the bare antenna and chip on a thin carrier, intended to be laminated or moulded into something else.
Is a thicker tag more durable?
Usually, because the encapsulation protects the antenna from creasing. Thickness also pushes the antenna slightly further from the reader, which costs a little range.