How to Erase and Reformat an NFC Tag So You Can Reuse It
Most NFC tags aren't one-and-done — erasing and reformatting clears the stored NDEF message so the same tag can carry new content. This guide covers what actually gets wiped, how Android and iPhone differ, and why a locked tag won't erase.
Quick answer
Erasing and reformatting an NFC tag clears its stored NDEF message and puts it back in a blank, writable state. Same physical tag, new content — instead of one in the drawer. That's different from locking a tag, which permanently blocks any future writes. One thing erasing never touches, no matter which app or platform you're on: the tag's UID can't be changed. If a tag isn't locked, you can erase and rewrite it as many times as its rated write-cycle limit allows — typically tens of thousands of cycles for common tags like NTAG213/215/216.
Step-by-step
An NFC tag's memory splits into a few distinct pieces: the writable NDEF area where your actual message lives, the factory-set UID, and, on some tags, lock bytes that control whether writes are allowed at all. Erasing only touches the first piece.
On Android, the mechanism behind every "erase" button is the NdefFormatable API. An app calls NdefFormatable.get(tag), then format(), clearing the tag's existing message and prepping it to accept a fresh one in the same step. That's what consumer apps like NFC Tools and NXP TagWriter are doing under the hood when you tap "erase" or "erase and format to NDEF." How much you can pack back onto a wiped tag depends on which NFC Forum tag type it is. Type 1 and 2 tags top out around 2KB; Type 5 tags trade capacity for range.
iPhone doesn't have an equivalent stock tool. Apple's CoreNFC framework ships no official, documented API for reformatting a tag, so you'll need a third-party app — NFC Tools is the common pick — that's already worked out the formatting path.
Common problems and fixes
"Tag Not NDEF formatted," or a write that just fails. This is the CoreNFC gap showing up directly. An Apple Developer Forums thread documents that NFCNDEFReaderSessionDelegate never even detects an unformatted tag, while NFCTagReaderSessionDelegate detects it but throws this error on write. Fix: use a dedicated reader/writer app rather than a plain NDEF-only reader.
The tag won't erase at all. Check whether it's been deliberately locked before assuming it's defective. Per Android Police's tag guide, setting a tag to read-only is one-way — once locked, it can't be erased or reformatted again, by design. Password protection is different: it blocks writes until the right password shows up, but it doesn't rule out reuse.
Writes fail silently, or old data reappears. Usually a capacity mismatch — you're writing more data than the tag's type allows. Check the tag's rated capacity before writing a large NDEF record.
Doing this on NFCore specifically
In NFCore, erasing a tag is a tap-hold-confirm flow: scan the tag, choose Erase, confirm. The app writes a blank NDEF message and the tag's ready for new content immediately. Once it's wiped, write anything from a URL to custom NDEF records without leaving the app.
Like everything else in NFCore, this happens entirely on-device — no account, no cloud upload, nothing tracked. Reusing tags for smart-home triggers, business cards, or a one-off project? Grab NFCore on the App Store or Google Play and erase your first tag in under a minute.
Frequently Asked Questions
Can any NFC tag be erased and reused?
Most writable NFC tags — NTAG213/215/216, MIFARE Ultralight, and similar NDEF-formatted stickers — can be erased and rewritten as many times as the tag's rated write-cycle limit allows, typically in the tens of thousands. The exception is a tag that's been deliberately locked to read-only. Once locked, it's permanent, and the tag can't be erased or reformatted again.
What's the difference between erasing and locking a tag?
Erasing clears the tag's stored NDEF message and puts it back in a blank, writable state so you can write new content. Locking does the opposite: it permanently sets the tag to read-only, so nobody — including you — can erase or overwrite it again. Lock a tag only once you're sure you won't need to reuse it.
Why can't I erase an NFC tag on iPhone the way I can on Android?
Apple's CoreNFC framework doesn't expose an official, documented API for reformatting an unformatted or previously-written tag the way Android's NdefFormatable class does. In practice, iPhone users need a third-party app like NFC Tools — one that's already solved that formatting gap — rather than relying on the stock Settings or Shortcuts NFC reader.
Does erasing a tag change its UID?
No. A tag's unique ID is burned in at the factory and can never be erased, changed, or reformatted, regardless of app or platform. Erasing only clears the writable NDEF memory area — the actual message content — not the UID.