Intelligent Mail® Barcode

The Intelligent Mail® barcode (IMb) is used to sort and track letters, cards and flats and offers greater versatility by allowing many services to be requested and embedded within one barcode. The Intelligent Mail barcode combines the data of the existing POSTNET™ and the PLANET Code® barcodes, as well as other data, into a single barcode. 

Who is the IMb for?

First Class Mail

First Class Mail



Standard Mail

Standard Mail


The Intelligent Mail barcode is a 65-bar Postal Service™ barcode used to sort and track letters and flats. It allows mailers to use a single barcode to participate in multiple Postal Service programs simultaneously, expands mailers' ability to track individual mailpieces, and provides greater mail stream visibility.

The IMb is required for use on letters and flats prepared for automation prices. This requirement affects First-Class Mail postcards, Insured Mail, Certified Mail, and any other mail using extra services currently available and appropriate for the class and shape of mail prepared for automation prices.

Registered Mail is ineligible for automation prices because of the way it is handled during processing.

There are three options for using the IMb: non-automation, basic automation, and Full-Service. In each of these cases, you'll want to ensure that you've tested your barcodes for compatability and accuracy or work with certified vendors. 

Featured Resources

Fact Sheets
Intelligent Mail® Barcode Resources

This document provides additional information and resources on IMb.

Barcode Decoder/Encoder

The IMb encoder and decoder tool allows you to convert Intelligent Mail® barcodes into numeric equivalents, or vice versa.

Quick Service Guides
Steps to Create the Intelligent Mail® Barcode

This document is a quick-reference guide for creating your Intelligent Mail® Barcodes.

Tech Guides
Intelligent Mail® Barcode (IMb) 4-State Specification

This document provides the specifications for generating and printing the Intelligent Mail® barcode (IMb) used in the U.S. Postal Service (USPS) mailstream.

User Guides
Intelligent Mail® Barcode Technical Resource Guide

This document contains the technical guide for Intelligent Mail® Barcode.

Unique Intelligent Mail® Barcodes (IMb) Initial Steps for Mailers

This presentation provides information on Intelligent Mail® Barcodes.

User Guides
Intelligent Mail® Barcode Technical Resource Guide

This document contains the technical guide for Intelligent Mail® Barcode.

Applications/ Forms
Mail Tracking and Reporting

Click here to apply for IMb Tracing

Fact Sheets
Barcode Identifier

This document provides an overview of Barcode Identifier field and a table of the optional endorsement line (OEL) codes for use within the Intelligent Mail barcode.

Related Products

Intelligent Mail® Package Barcode (IMpb) ACS™

IMpb ACS allows parcel mailers who print the Intelligent Mail package barcode to receive an electronic address correction using that barcode.

Intelligent Mail® Barcode (IMb) Encoder Software and Fonts

The Postal Service provides Intelligent Mail® barcode files, fonts and encoders, available for download.


For questions, please call 1-877-640-0724 or email