Free tool
RFID card number converter and Wiegand 26/34 calculator
Type the number your reader, card print or access controller shows. Get every other representation of the same ID — decimal, hex, byte-reversed, Wiegand 26 and Wiegand 34 with the full bit string.
| 10-digit decimal (32-bit) | — |
|---|---|
| 8H hex | — |
| Hex, byte-reversed | — |
| Decimal, byte-reversed | — |
| Wiegand 26 facility, card | — |
| Wiegand 26 bit string | — |
| Wiegand 34 facility, card | — |
| Wiegand 34 bit string | — |
| EM4100 customer / version byte | — |
How the conversions work
Most 125kHz EM4100-compatible cards and 13.56MHz MIFARE UIDs are handled by readers as a 32-bit number. Printing the same number in base 10 gives the familiar 10-digit value (for example 0012345678); printing it in base 16 gives 8 hex characters (00BC614E). An EM4100 chip also stores one extra leading byte (the customer or version byte), which most keyboard readers do not output.
Wiegand 26 sends 24 of those bits: an 8-bit facility code and a 16-bit card number, framed by an even-parity bit (covering the first 12 data bits) and an odd-parity bit (covering the last 12). Wiegand 34 sends all 32 bits as a 16-bit facility code and 16-bit card number, with parity over each half. That is why a card showing 188,24910 in Wiegand 26 can show a different facility code on a Wiegand 34 controller. See our guides on card number formats and Wiegand 26 vs 34 for the bit-level detail.
| Shown as | Example | Where you see it |
|---|---|---|
| 10-digit decimal | 0012345678 | USB keyboard readers (default), card print |
| 8H hex | 00BC614E | Readers set to hex output, MIFARE UID tools |
| Wiegand 26 (FC, CN) | 188,24910 | Access controllers, card print |
| Wiegand 34 (FC, CN) | 188,24910 — identical to Wiegand 26 only when the top byte is 00 | Controllers set to 34-bit input |
Need a reader that outputs exactly the format your software expects? Many of our USB readers can be configured for decimal, hex or reversed output, and our Wiegand wall readers such as the L410-W and Q420-M switch between 26 and 34 bits.
Frequently asked questions
Why does my reader show a different number from the one printed on the card?
The chip holds one binary ID, but readers and printers display it in different ways: a 10-digit decimal of the 32-bit value, an 8-character hex string, or a Wiegand facility code and card number. All of them can be the same card. Enter any one of them above to see the others.
What is the "188,24910" style number on 125kHz cards?
It is the Wiegand 26 view of the ID: the first number is the 8-bit facility code (0–255) and the second is the 16-bit card number (0–65535), both taken from the lower 24 bits of the ID. The 10-digit number usually printed next to it is the full 32-bit value in decimal.
What does byte-reversed mean for MIFARE UIDs?
Some software and readers send the 4-byte UID least-significant byte first. The card is identical; only the byte order differs. If your system shows a number that does not match, compare it with the byte-reversed values.
Is the facility code the same in Wiegand 26 and Wiegand 34?
No. Wiegand 26 carries 24 data bits (8-bit facility code + 16-bit card number); Wiegand 34 carries 32 data bits, commonly split as a 16-bit facility code + 16-bit card number. The same card therefore shows a different facility code in the two formats whenever the top byte of its 32-bit ID is not zero.
Match the reader output to your software
Tell us what your system expects — decimal, hex, reversed, Wiegand 26 or 34. We confirm which models can output it and ship them configured before delivery.