MaxiCode example. This encodes the string "Wikipedia, the free encyclopedia".

MaxiCode is a public domain, machine-readable symbol system originally created by the United Parcel Service (UPS) in 1992. Suitable for tracking and managing the shipment of packages, it resembles an Aztec Code or QR code, but uses dots arranged in a hexagonal grid instead of square grid. MaxiCode has been standardised under ISO/IEC 16023.

A MaxiCode symbol (internally called "Bird's Eye", "Target", "dense code", or "UPS code") appears as a 1-inch square, with a bullseye in the middle, surrounded by a pattern of hexagonal dots. It can store about 93 characters of information, and up to 8 MaxiCode symbols can be chained together to convey more data. The centered symmetrical bullseye is useful in automatic symbol location regardless of orientation, and it allows MaxiCode symbols to be scanned even on a package traveling rapidly.

Structured Carrier Message

MaxiCode symbols using modes 2 and 3 include a Structured Carrier Message containing key information about a package. This information is protected with a strong Reed–Solomon error correction code, allowing it to be read even if a portion of the symbol is damaged. These fields include:

  1. A 4-bit indication of the mode in use, currently either mode 2 or mode 3.
  2. A national or international postal code. MaxiCode supports both numeric postal codes (e.g. a ZIP Code), and alphanumeric postal codes.
  3. A 3-digit country code encoded per ISO 3166
  4. A 3-digit class of service code assigned by the carrier

The structured portion of the message is stored in the inner area of the symbol, near the bull's-eye pattern. (In modes that do not include a structured portion, the inner area simply stores the beginning of the message.)

Application-specific information

Irrespective of mode, a variable amount of application-specific information can be encoded in a MaxiCode symbol. This format of this additional data is not strictly defined, and amongst other information may include:


UPS labels use Mode 2 or Mode 3 MaxiCodes.


  1. ^ Dr. Randal C. Nelson. "Bar Codes". University of Rochester. Retrieved 2023-02-20.
  2. ^ "ISO/IEC 16023:2000". International Standards Organization. Retrieved 20 December 2018.Closed access icon

External links