Magstripe
Payment Track 1 (format B) and Track 2. Keep the start and end sentinels.
CRC uses each track’s ASCII bytes, including sentinels and excluding line breaks. CRC, LRC, and odd parity are calculated from text, not verified against a physical card.
Luhn checksum
Enter up to 19 digits, including the final check digit. Spaces and hyphens do not count toward the limit.
Includes the check digit. For checksum testing, not payment use.
A passing checksum does not confirm that a card exists, is active, or can be charged.
Summary results mask account numbers. Expanded encoding tables expose the input characters and bits. Nothing is saved.
References: LRC & parity rules ↗ · CRC variants ↗ · Test numbers ↗ · Track formats ↗ · Luhn algorithm ↗
Calculator reference
Verification evidence and limitations →
What it calculates
Decodes track 1/2 text and checks number and track-related check values.
Inputs and methods
Pasted track data or a number up to 19 digits for Luhn. Track checks depend on the chosen input representation.
Worked example
In Luhn, enter synthetic number 4111111111111111.
Luhn: passed
Specification and limits
Luhn does not verify an account. CRC16 is not the magnetic-track LRC; character parity requires encoded track bits.
ISO standards catalogue ↗