Intelligent Mail

USPS Intelligent Mail barcode

1D barcode65 bars

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What is Intelligent Mail?

The United States Postal Service four-state barcode that combines routing and tracking information in one symbol. Each bar can be full, ascender, descender, or tracker.

How it is structured

A fixed 65-bar symbol encodes a 20-digit tracking code plus up to 11 routing digits. Data is protected by an 11-bit frame check sequence and mapped into four-state bars.

Where it is used

US letter and flat mail tracking, sorting, address correction, and postal automation.

Primary specification

See USPS Intelligent Mail Barcode specification for the authoritative specification or publisher record.