June 25, 2026 · 3 min read
What Do Different Carriers' Tracking Numbers Actually Look Like?
Why format matters
Picking the wrong carrier for a tracking number is one of the most common reasons a tracking link 'doesn't work' — the number is real, it's just being checked against the wrong carrier's system.
Rough formats by carrier
UPS: usually starts with '1Z', 18 characters total. FedEx: typically 12 to 22 digits, no letters. USPS: often 20 to 22 digits, or two letters followed by 9 digits and 'US'. DHL: commonly 10 to 11 digits, or a mix of letters and numbers depending on service type. These aren't exact rules — carriers use multiple formats depending on the shipping service — but they're a useful sanity check.
Regional carriers vary more
Carriers like Aramex, Yalidine, or SMSA don't publish as strict a public format, so if a number looks unusual for one of these, it's less of a red flag than it would be for a major international carrier — just double-check the carrier selection is correct.
When in doubt
If a tracking link shows an error, the two most common causes are: a mismatched carrier, or a typo in the code (numbers and letters like 0/O or 1/I are easy to swap when copying by hand). Re-check both before assuming the shipment itself has a problem.
Ready to generate a tracking link?
Go to the tool