How many tags can you read in a row on a phone?
As many as you like, one at a time. Nothing wears out on either side, so the limit is the rhythm rather than a count. What differs is how much friction each read carries, and that is a platform difference rather than a hardware one.
Nothing wears out
Reading a tag consumes no write cycles, so a tag read a thousand times is electrically identical to one read once.
The phone is not consuming anything either, beyond a little power. There is no counter, no quota and no degradation.
So the question is never how many. It is how fast, and how much attention each one takes.
The rhythm is the limit
Each read needs the phone brought to the tag, held still long enough, and moved away before the next.
Moving away matters. A phone left over a tag will not necessarily notice the next one presented, and two tags close together compete.
Content size sets how long each read takes, which is one more reason a short address beats a payload when a person is doing this repeatedly.
Across a hundred tags, seconds per tag become the whole job.
Where the platforms differ
On Android, a tag can be handled by the system or claimed by an application in the foreground, and successive tags flow with little ceremony.
On iOS, reading through an application happens inside a session with a system sheet. One session can read tag after tag if the application keeps it open, until it times out. An application that closes it after each tag makes the rhythm start, tap, dismiss, repeat.
That difference is barely noticeable over five tags and substantial over five hundred.
For a production or stocktaking task, it is a reason to prefer Android as the working device, independently of what the tags will be tapped by later.
Setting up a bench
Separate unread from read physically, into two containers. It is the single change that prevents the confusion of reading the same tag twice.
Keep tags apart while working, since a stack of tags near the phone is several tags competing for one field.
Rest the phone rather than holding it, and bring tags to the phone rather than the reverse. It is faster and steadier.
And for genuinely high volume, use a dedicated reader on a stand. A phone is adequate for tens and tiring for hundreds.
Frequently asked questions
Does reading tags wear out my phone?
No, beyond a little battery. There is no counter or quota on either side of the exchange.
Why does the second tag not read?
Usually the phone has not been moved away from the first, or the tags are close enough to compete. Separate them and lift between reads.
Is Android faster for reading many tags?
In practice yes. An iOS session has to be started from the application and times out, even when it reads several tags, and an application that closes it after each tag starts one for every tag. Over hundreds of tags that difference is substantial.
Should I use a dedicated reader?
For hundreds of tags at a fixed position, yes. A phone is fine for tens and tiring beyond that.