4 Byte or 7 Byte UID Mifare Classic

[mark4]

Hi ,

Can anybody tell me how I can tell if my Mifare classic chip is a 4 byte or 7 byte UID please? 

I have the NXP Mifare reader app on my phone but I don't know which part of the data relates to the UID byte size. 

Many thanks 

[IvanRuiz]

Hello,

You can easily check the UID length with the NFC TagInfo App available for Android / iOS in their respective stores.

Hope it helps.

BR,

Ivan.