The simplest answer is:
NFC is actually a type of RFID technology.
However, in everyday use, people usually distinguish them like this:
| Type | Frequency | Typical Use |
|---|---|---|
| RFID (LF) | 125KHz | Door access systems |
| NFC / HF RFID | 13.56MHz | Smartphones, payments, NFC apps |
So when people ask:
"Is my fob NFC or RFID?"
They usually mean:
Is it a traditional low-frequency RFID fob?
or
Is it a smartphone-compatible NFC fob?
Try Scanning It With Your Smartphone:
If your phone can read it:
Your fob is most likely:
NFC
or 13.56MHz HF RFID
Common compatible chips include:
NTAG213
NTAG215
NTAG216
MIFARE Classic
MIFARE DESFire
Ultralight
If your phone cannot detect it:
It is probably:
125KHz LF RFID
such as EM4200, TK4100, T5577, HID Prox, etc.
Most smartphones cannot read 125KHz RFID.