USPS Tracking ID: How to Find and Read Your USPS Number

A USPS tracking ID is the unique number the Postal Service assigns to a tracked mailpiece, printed below the barcode on the label and on your mailing receipt. Domestic USPS tracking IDs are usually 20 to 22 digits and start with a 9, while international ones are 13 characters: two letters, nine digits and a two-letter country code such as “US.”

This guide covers USPS tracking IDs only. If you shipped with UPS instead, see UPS tracking.

What Is a USPS Tracking ID?

A USPS tracking ID (USPS also calls it a tracking number or article number) links your package to the scan events recorded as it moves through the postal network. USPS says tracking is included automatically with most domestic products large enough to carry a label, including mail to APO, FPO and DPO addresses. First-Class Mail postcards, letters and flats don’t get one unless you add a service such as Certified Mail.

The ID doesn’t speed up or guarantee delivery. It records where the item was last scanned: at acceptance, at processing facilities, at the destination Post Office and at delivery. Scans happen at checkpoints rather than continuously, so a day or two without a new event during transit is normal. Our overview of package tracking services explains how carrier scan networks generate these updates.

Where Do You Find Your USPS Tracking ID?

USPS lists three places to find the number: your sales or mailing receipt, the online label record if you bought postage online, and the digits printed below the barcode on the item itself. Where you look depends on whether you sent the package or are waiting for it.

If you bought shipping labels online, the tracking ID is saved in the account you used to buy them. Read the human-readable number under the barcode rather than other reference numbers on the label, such as a ZIP routing code or an order ID.

USPS states that Post Office staff and its Customer Care Center can’t recover a lost tracking number. If you’re the recipient, the sender is your best source. If you’re the sender, check your receipt, email and label history first.

How Do You Read a USPS Tracking ID Format?

USPS tracking IDs follow a few predictable patterns. The table below uses the sample formats USPS publishes, with zeros standing in for the unique digits.

Treat the leading digits as a hint, not a decoder. Labels printed by different systems use different prefixes for the same service, so two Priority Mail packages can carry numbers that begin differently. The tracking results page at USPS.com always names the actual service, so rely on that. For a deeper breakdown of prefixes, see what a USPS tracking number starts with.

What Do the Letters in an International USPS Tracking ID Mean?

International tracking IDs follow the Universal Postal Union’s S10 standard: two service-indicator letters, eight serial digits, one check digit and a two-letter country code. The final “US” means the item entered the mail in the United States. The first letter generally signals the product type: E for express (EMS) items such as Priority Mail Express International, C for parcels such as Priority Mail International, R for registered items and L for tracked letter-post items.

How Do You Track a Package With a USPS Tracking ID?

You can use your tracking ID through several official USPS channels. All of them read from the same tracking record, so the status will match.

• USPS.com: Enter the number on the USPS Tracking page. You can enter several numbers at once, separated by commas, and sign up for text or email updates on the results page.
• Text message: Send the tracking number as a text to 28777 (2USPS). Standard message rates may apply, and replying STOP ends all active text tracking requests.
• USPS Mobile app: Scan the barcode or type the number to save it to your list.
• Phone: USPS’s automated tracking line at 1-800-222-1811 reads back the latest status.
• Informed Delivery: Recipients who enroll see incoming tracked packages for their address without needing the number.

For what each status means and what to do when an update stalls, our complete guide to USPS tracking covers every major scan event.

How Long Does a USPS Tracking ID Stay Active?

USPS keeps standard tracking records for 120 days. Services with signature or accountability features are kept longer, according to USPS.

If you may need the record later, for a claim, a dispute or a legal deadline, save or print the tracking page while it is still available. Our guide on how to send Certified Mail explains how that service’s longer record retention works in practice.

How Fast Should Your USPS Package Move?

Your tracking ID is tied to a specific service, and that service sets the delivery expectation shown in tracking. USPS publishes these delivery ranges:

First-Class Package Service no longer exists; USPS folded it into USPS Ground Advantage in July 2023, so new labels show Ground Advantage instead. For a service-by-service look at how long Priority Mail takes, including what the expected delivery date in tracking really means, see our dedicated guide.

Why Isn’t Your USPS Tracking ID Working?

Most “not found” results have a simple cause. A newly created label shows no scans until USPS physically accepts the package, so allow up to a day after drop-off. A single transposed digit also returns no result, so compare the number against the receipt digit by digit, without spaces or dashes.

If the number is right but scans have stopped, the package is usually between facilities rather than lost. Wait out the delivery range for the service before taking action, then use the USPS Help request or Missing Mail search on USPS.com.

Does Shipping Through ParcelPath Change Your USPS Tracking ID?

No. A USPS label created through ParcelPath carries a standard USPS tracking ID that works on USPS.com, by text and in the USPS app like any other. ParcelPath is free to use, with no subscription or per-label fee, and offers up to 89% off USPS retail rates. You can compare USPS and UPS prices for a specific package in the ParcelPath rate calculator, and our eCommerce shipping guide covers how online sellers set up shipping.

Frequently Asked Questions

How many digits is a USPS tracking ID?

Most domestic USPS tracking IDs are 20 to 22 digits long, with 22 the most common, and they usually begin with a 9. International USPS tracking IDs are 13 characters, two letters, nine digits and “US,” while Global Express Guaranteed uses a 10-digit number that starts with 82.

Can I find a USPS tracking ID without the receipt?

Sometimes. If you bought postage online, the ID is saved in your label history and confirmation email. Recipients can ask the sender or check Informed Delivery. USPS says Post Office staff and its Customer Care Center have no way to recover a lost tracking number, so the sender’s records are the main source.

How long can I track a package with a USPS tracking ID?

Standard USPS Tracking records stay available for 120 days. Signature Confirmation records are kept for one year, and Priority Mail Express, Certified Mail, Registered Mail and Adult Signature records for two years. Save the tracking page if you might need proof of delivery later.

Does every USPS item have a tracking ID?

No. USPS includes tracking automatically on most domestic packages, but First-Class Mail postcards, letters and flats aren’t eligible unless you add an extra service such as Certified Mail. Some USPS Marketing Mail parcels need tracking added for a fee, and some international products have destination limits.

Sources

• USPS FAQ: USPS Tracking, The Basics
• USPS FAQ: How to find your tracking number
• USPS: Mail and Shipping Services
• S10 (UPU standard) tracking identifiers

Part of our USPS Tracking guide. Related: USPS Tracking and Delivery, USPS Tracking Not Updating, USPS Tracking Not Updating After Drop Off.

More in this section: USPS change of address, USPS locations, USPS services, USPS tracking.