Understanding Your USPS Tracking Number
Every USPS package comes with a tracking number — a unique string of digits that allows both you and the postal service to follow your shipment from origin to destination. But what do all those numbers actually mean? This guide breaks it down clearly.
USPS Tracking Number Formats
USPS uses several different tracking number formats depending on the service used. Here are the most common ones:
| Service | Format | Example Length |
|---|---|---|
| Priority Mail / Priority Mail Express | 22 digits | 9400 1000 0000 0000 0000 00 |
| Certified Mail | 22 digits starting with 70 | 7010 3090 0000 0000 0000 |
| First-Class Package | 22 digits | 9400 1000 0000 0000 0000 00 |
| International Mail (with tracking) | 13 characters (letters + numbers) | EA 000 000 000 US |
| USPS Retail Ground | 22 digits | 9400 1000 0000 0000 0000 00 |
Breaking Down a Standard USPS Tracking Number
A typical 22-digit USPS tracking number contains embedded information:
- First 2 digits: Indicate the mail class or application identifier (e.g., 94 for domestic Priority Mail).
- Digits 3–8: Represent a routing or service code assigned by USPS.
- Digits 9–20: The unique package identifier — this is what makes every number distinct.
- Last digit: A check digit used to verify the number is valid and wasn't mistyped.
International Tracking Number Format
International USPS tracking numbers follow the Universal Postal Union (UPU) standard format:
- Two letters at the start (e.g., EA, CP, RR) indicate the service type.
- Eight digits form the unique identifier.
- A single check digit follows.
- Two letters at the end (e.g., US) indicate the country of origin.
Where to Find Your Tracking Number
- Your receipt: Printed at the bottom of any USPS mailing receipt.
- Shipping confirmation email: Sent by the retailer or shipper after dispatch.
- USPS label: Printed directly on the package as a barcode with digits below.
- Online order history: Most e-commerce platforms store tracking numbers in your account.
How to Track Your Package
Once you have your tracking number, you have several options:
- Visit usps.com/track and enter the number in the search box.
- Text your tracking number to 28777 (2USPS) to get SMS updates.
- Call 1-800-222-1811 and follow the automated tracking prompts.
- Use the USPS Mobile app available on iOS and Android.
Common Tracking Number Issues
If your tracking number isn't working, consider these possibilities:
- Too soon after shipping: It can take up to 24 hours for a new tracking number to appear in the USPS system.
- Typo in the number: Double-check every digit — tracking numbers have no spaces when entered online.
- Service doesn't include tracking: Standard First-Class Mail letters do not come with tracking unless upgraded.
Understanding your USPS tracking number gives you full visibility into where your package is and what stage of delivery it's in. Bookmark the USPS tracking page and keep your number handy until your package arrives.