What data is stored on a payment card's magnetic stripe?
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04/09/2025 15:37 PM
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Magnetic stripes on payment cards, often referred to as "magstripes", are divided into three tracks of data. These are encoded directly to the magstripe. Only Track 1 and Track 2 are actively used in payment card processing. Track 3 is rarely used and may not always be present on a card.
Both Track 1 and Track 2 contain enough basic information for processing payment card swipes. Most card readers will be able to read both Track 1 and Track 2 data, in case one of the tracks has become unreadable.
Track 1 Data Structure
| Field Name | Length | Comments |
|---|---|---|
| Start Sentinel (SS) | 1 character | Indicates the beginning of Track 1; set to "%" |
| Format Code (FC) | 1 character | Indicates the card type; "B" indicates a credit/debit card |
| Primary Account Number (PAN) | up to 19 digits | Always numerical; usually set to the credit/debit card number |
| Field Separator (FS) | 1 character | Delimits Track 1 fields; set to "^" |
| Name | 2-26 characters | Account holder's name |
| Field Separator (FS) | 1 character | Delimits Track 1 fields; set to "^" |
| Expiration Date (ED) | 4 digits | Always in the format YYMM |
| Service Code (SC) | 3 digits | Indicates what types of charges can be accepted |
| Discretionary Data (DD) | Variable* | Determined by card issuer--may include Card Code and/or PINs |
| End Sentinel (ES) | 1 character | Indicates the end of Track 1; set to "?" |
| Longitude Redundancy Check (LRC) | 1 character | Used to verify that Track 1 was read accurately |
* Track 1 Data cannot exceed 79 characters, including all Sentinels, Field Separators, and the LRC. The length of Discretionary Data is restricted as a result and tends to hold fairly short values.
The format for Track 2 Data was developed by the American Banking Association (ABA). It tends to be much shorter and holds less information:
Track 2 Data Structure
| Field Name | Length | Comments |
|---|---|---|
| Start Sentinel (SS) | 1 character | Indicates the beginning of Track 2; set to ";" |
| Primary Account Number (PAN) | up to 19 digits | Always numerical; usually set to the credit/debit card number |
| Field Separator (FS) | 1 character | Delimits Track 2 fields; set to "=" |
| Expiration Date (ED) | 4 digits | Always in the format YYMM |
| Service Code (SC) | 3 digits | Indicates what types of charges can be accepted |
| Discretionary Data (DD) | Variable* | Determined by card issuer--may include Card Code and/or PINs |
| End Sentinel (ES) | 1 character | Indicates the end of Track 2; set to "?" |
| Longitude Redundancy Check (LRC) | 1 character | Used to verify that Track 2 was read accurately |
* Track 2 Data cannot exceed 40 characters, including all Sentinels, the Field Separator, and the LRC. The length of Discretionary Data is restricted as a result and tends to hold fairly short values.
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