USPS Flat Mail Tracking

Flat mail or Large Envelopes(these terms are used interchangeably) have a maximum size limit of 12" x 15" and can not be more than 3/4" thick. As long as a mailpiece is within these specifications, it is considered machineable mail which means it can be mailed and tracked via LetterTrack. Our proprietary software allows you to print on envelopes of various formats or address labels in various sizes and adds a USPS intelligent mail barcode above the address block of the recipient of your mailpiece. As your flat mail travels through the postal system to its destination, the intelligent mail barcodes on your mailpieces are scanned at each facility. LetterTrack, captures these scans to provide the seller and buyer with real time tracking emails each time a mailpiece is scanned. The final scan each mailpiece receives is at the local post office of the destination city. When a mailpiece reaches the destination post office to be placed on a USPS postal truck for delivery, the mailpiece is marked as Out for Delivery. Your mail will reach the recipient in 3 business days since it is being sent via First Class mail.

Real-time tracking dashboard

Searchable tracking screen 

LetterTrack has a tracking screen that allows you to track all of your mailpieces using various search filters. Search using any part of the recipients address, by date range, or by information you are able to populate into an internal reference and order number field.  

Getting Started

Register for your Free Trial

Registering your account is free and takes less than 5 minutes. Your account will have 5 free transactions so you can try LetterTrack at no obligation.

Import a file or enter the recipients addresses one at a time  

Print your envelopes or address labels using your desired format, which will include a USPS Informed Visibility mail tracking barcode above the address. 

Place regular postage on your envelopes and mail them

Apply regular postage to your envelopes using USPS stamps, online postage providers like or with a postage meter.  Place the envelopes in your mailbox for your postal carrier to pickup, drop them in a USPS drop box, or bring them to your local post office.  

Track flat mail

Track flat mail and pay regular postage

Track large envelopes and pay regular postage

Save money by tracking your flat mail instead of paying the increased postage with package/parcel mail