RC522 ID Converter

Paste the UID your phone app shows for a tag (e.g. 04:53:F2:5B:4E:61:81). This tool outputs the RC522-style ID your kiosk expects.

How it works: for 7/10-byte UIDs, it outputs 88 + first 3 UID bytes + BCC, where BCC = XOR of 88 and those 3 bytes. For 4-byte UIDs, you can optionally append the BCC (XOR of the 4 bytes).