Postmarked Mail vs. Dated Postage Stamp

When receiving mail, primarily First Class Mail, there are stamps on the envelope to indicate when an envelope was sent out. Let's go over what these stamps actually mean.

Postmarked Mail

When mail is postmarked, the mail is stamped with an imprint (usually in black ink) on the address side of your envelope. The postmark will show the location and the date the envelope was accepted at the post office:

While delays in transit with First Class Mail can be common, the postmark date can help you understand when the envelope was actually received by the USPS.

Postage Stamp With Date

You may see printed postage stamps with a date on there. This is frequently done when using a postage printing software such as the ones from Pitney Bowes:

The Pitney Bowes stamp comes from the mailer's postage printing machine. The stamp provides information about where the postage was printed from, the date the postage was printed, and the postage amount that was paid.

The date printed on the Pitney Bowes stamp is not necessarily the date that it was mailed out. It only reflects the date that postage was printed.

With this in mind, the actual mailing date could depend on when the mailer actually hands over the mail to USPS's possession. For example, a mailer could print the postage 1-2 days before going to the Post Office to drop it off with USPS.