How Intelligent Mail barcode (IMb) tracking works
Ordinary First-Class letters don't come with a tracking number, but every one that runs through USPS automated equipment can still be followed - if it carries an Intelligent Mail barcode. This page explains what the barcode holds, where the scan data comes from, and what to expect on the tracking page.
What is in the barcode
The Intelligent Mail barcode (IMb) is a row of 65 bars of four kinds: full, ascending, descending and short "tracker" bars. Together they encode up to 31 digits:
- Barcode ID (2 digits) - presort and endorsement information.
- Service Type ID (3 digits) - the mail class and services requested, such as First-Class Mail with tracing.
- Mailer ID (6 or 9 digits) - the USPS-assigned identity of the party responsible for the barcode. Scan data is reported to this ID.
- Serial number (9 or 6 digits) - makes each piece unique. USPS requires a barcode to stay unique for at least 45 days.
- Routing code (0, 5, 9 or 11 digits) - the destination ZIP, ZIP+4 or delivery point.
The first four parts make up the 20-digit tracking code; add the routing ZIP and you have the full number printed with every IV-MTR Tracking label. Paste either one into the tracking page.
Where the scans come from
As a piece moves through mail processing, sorting machines read its barcode. USPS collects those reads in Informed Visibility Mail Tracking & Reporting (IV-MTR) and sends them to the holder of the Mailer ID. We hold the Mailer ID on every label we issue, so the scan events arrive here and appear on the piece's tracking page.
What to expect
- First scan: usually the origin processing facility, within a day of the piece entering the mail.
- In transit: one or more processing scans as the piece is sorted toward its destination. USPS may include an expected delivery date.
- Destination: letters often have no delivery scan. The last processing scan at the destination facility - typically the morning it goes out with the carrier - is usually the final event.
- Timing: USPS sends scan data in batches, so an event can show up a few hours after the scan itself.
Adding tracking to your own mail
- Create an account and buy a label pack - 12¢ per label, and credits never expire.
- Enter an address or upload a spreadsheet. Each label gets its own barcode.
- Print at actual size directly on envelopes (#10, #6¾, A2, A6, A7, A9, C5 or a #10 window sheet), on Avery 2×4 or 1¾×4 sheets, or on 4×6, 4×2-5/16, 1-1/8×3-1/2, 1-1/2×3-1/2 or Brother 2.3" label rolls.
- Mail it with regular First-Class postage, or email the label to a customer who will mail something back to you.