My tag only reads when touching: is that normal?
Normal for most tags with most phones. NFC is a contact range technology and the published figures describe generous readers rather than handsets. What would be abnormal is a card sized tag needing pressure, or any tag that read further a week ago.
What normal looks like
A small sticker read by a phone works at contact or a few millimetres. A card sized tag manages a little more. Neither works across a desk, and neither is faulty for that.
The figures quoted for the technology assume a reader with a large antenna and a strong field. A phone has a small coil and a modest field, so it sits at the bottom of that range.
So if your tag works when the phone touches it, and works every time, you have a working deployment. The question is worth asking once and then dropping.
What is not normal
Needing pressure. If pressing harder helps, something mechanical is happening rather than something electromagnetic, and the tag is probably damaged or sitting on a compressible surface with metal behind it.
A card sized tag at contact only. A card has a large antenna and should give you a centimetre or two with most phones. If it does not, look at what is behind it.
A change over time. A tag that read at two centimetres last month and needs contact today has had something change, and that is worth investigating rather than accepting.
Working for you and not for others. That is a gesture and antenna position problem rather than a range problem.
Three things that shrink it to contact
A small tag. Range follows antenna size, so a coin sized sticker has little to give and a card has more.
The surface. Metal behind a tag cancels the field, and a partly conductive surface reduces it. This is the cause most often missed because the tag worked perfectly on the bench.
Whatever is between. A thick case, a metal plate for a magnetic mount, a card in a wallet case, or a foam spacer all add distance or absorb field.
Living with contact range
Design for a touch rather than a wave. Say so on the tag if members of the public will use it.
Print a target. People aim at a symbol and wave vaguely at a blank surface, and the difference in success rate is larger than a step up in tag size.
Use the largest tag the object allows, since range gained this way costs nothing once the object is fixed.
And if the requirement genuinely exceeds contact, change the reader rather than the tag. No tag size turns a phone into a long range reader.
Frequently asked questions
Should a tag read from several centimetres?
A card sized tag with a good phone can. A small sticker generally cannot, and quoted distances for the technology assume readers far more capable than a handset.
Does pressing harder help?
It should not, and if it does something mechanical is involved. Look for damage or a compressible mounting with metal behind it.
Is my phone weak?
Field strength does vary between models and the tag and surface usually matter more. Compare with a second phone before blaming either.
Can I increase the range?
A larger tag, a better surface and removing whatever sits between are the three that work. Nothing about the chip changes it.