USPS tracking number format: official examples, length, and prefixes

A common USPS tracking number is a long numeric code. One official USPS example looks like this:

9400 1000 0000 0000 0000 00

That format is used for USPS Tracking. Other USPS services use different examples, including 9205 5000 0000 0000 0000 00 for Priority Mail, 9407 3000 0000 0000 0000 00 for Certified Mail, and international formats like CP 000 000 000 US.

If you have a USPS tracking number, paste it into the tracker on this page to check the latest status.

Quick answer

Many USPS domestic tracking numbers have 22 digits. They are often shown in groups to make them easier to read, but the spaces are just formatting.

USPS also uses shorter and letter-based formats for some services. For example, international USPS tracking numbers often use two letters, nine numbers, and end with US.

These are format examples, not working tracking numbers.

What does a USPS tracking number look like?

A USPS tracking number may be numeric only:

9400100000000000000000

Or it may be shown with spaces:

9400 1000 0000 0000 0000 00

Both point to the same kind of number. The spaces only make the number easier to read.

Some USPS numbers include letters, especially international mail:

CP 000 000 000 US

For international formats, the first two letters usually identify the mail type, the middle part is nine digits, and US at the end means the item was issued by USPS in the United States.

USPS tracking number examples by service

Here are the USPS sample numbers people most often search for.

Do not paste these examples into a tracking tool and expect a result. They are masked samples.

How long is a USPS tracking number?

There is no single USPS tracking number length for every service.

The most common domestic examples have 22 digits. Some USPS services use 10 digits. Some international USPS numbers use 13 characters: two letters, nine numbers, then US.

A number can still be valid if it does not match the first example you found online. The service type matters.

What do USPS tracking numbers start with?

USPS tracking numbers can start with several prefixes.

The prefix can give you a clue about the service, but it is not something most customers need to decode perfectly. If the number is valid, the tracking page should show the current status.

If your number starts with one of these prefixes, USPS is a good guess. If it starts with something else, it may still be USPS, or it may belong to another carrier or marketplace shipping program.

Domestic vs international USPS tracking numbers

Domestic USPS tracking numbers are usually numbers only.

Example:

9205 5000 0000 0000 0000 00

International USPS tracking numbers often use letters at the beginning and at the end.

Example:

CP 000 000 000 US

That difference matters because many people copy an international number and think the letters are extra text. They are not. If your USPS tracking number has letters, copy the full code, including the letters.

Loose USPS tracking number patterns

If you are validating USPS tracking numbers in a form, keep the rules loose. USPS has multiple services and formats, so one strict pattern will reject valid numbers.

A practical validation approach is:

Domestic numeric: 10 to 22 digits
International: 2 letters + 9 digits + US

For developers, that can look like this:

^\d{10,22}$
^[A-Z]{2}\d{9}US$

Those patterns are useful for catching obvious mistakes. They should not be treated as proof that a shipment exists. The only real test is whether USPS returns tracking information for the number.

Where to find your USPS tracking number

Look for the USPS tracking number in these places:

• the Post Office sales receipt
• the mailing label, usually under the barcode
• the shipping confirmation email from the store or sender
• your USPS.com account or shipping history
• the email notification sent by the seller
• the peel-off tracking label, if one was provided

If you are the recipient and cannot find the number, ask the sender. USPS generally needs the tracking number to look up the item.

Why your USPS tracking number is not working

A USPS tracking number may not work right away. That does not always mean the number is fake.

Common reasons include:

1. The label was created, but USPS has not scanned the package yet.
2. The sender gave you an order number instead of a tracking number.
3. You copied an extra space, dash, or word from the email.
4. You mistyped a letter or number.
5. The item is moving through a partner or international postal system.
6. Tracking has not updated since the last facility scan.

Try copying only the number, without spaces or extra words. If the number still does not work after a day or two, contact the sender and ask them to confirm the USPS tracking number.

USPS tracking number vs order number

A USPS tracking number follows the package. An order number follows the purchase.

They are easy to mix up because stores often show them on the same page.

If USPS says the number is not found, check whether you copied the tracking number or the order number.

Be careful with fake USPS tracking texts

A tracking number format can look real even when the message is fake.

Be careful with texts or emails that claim a USPS delivery failed and ask you to click a strange link, pay a small fee, or re-enter personal information. If you were not expecting the message, copy the tracking number and check it through USPS.com or a trusted tracking page instead.

A real-looking prefix like 9400 or 9205 is not enough to trust a message.

Common USPS tracking statuses

USPS status wording can vary, but these are the updates most people run into.

If tracking stops updating for a short time, it may simply be between scans.

FAQ

What is an example of a USPS tracking number?

A common USPS Tracking number example is 9400 1000 0000 0000 0000 00. Priority Mail often uses a similar 22 digit format, such as 9205 5000 0000 0000 0000 00.

How many digits are in a USPS tracking number?

Many USPS domestic tracking numbers have 22 digits, but the length depends on the service. Global Express Guaranteed can use a 10 digit format, and some international USPS numbers use 13 characters with two letters, nine numbers, and US at the end.

What do USPS tracking numbers start with?

Common USPS prefixes include 9400, 9205, 9407, 9303, 9270, 9208, and 9202. Some international USPS numbers start with letters such as CP, EC, EA, or RA.

Do USPS tracking numbers have letters?

Some do. Many domestic USPS tracking numbers are numeric only, but international formats often use letters, such as CP 000 000 000 US or EC 000 000 000 US.

Is CP 000 000 000 US a USPS tracking number?

It is an example of a Priority Mail International format used by USPS. The CP prefix and US ending are part of the format.

Is EA 000 000 000 US a USPS tracking number?

It can be. USPS lists EA 000 000 000 US as a Priority Mail Express sample number.

Where can I find my USPS tracking number?

Check your Post Office sales receipt, the barcode area on the mailing label, your shipping confirmation email, your USPS.com account, or the order details from the store. If you are the recipient, the sender can usually resend it.

Why is my USPS tracking number not found?

The package may not have been scanned yet, the label may be new, or the wrong number may have been entered. It also happens when someone copies the store order number instead of the USPS tracking number.

Are the USPS tracking examples on this page real?

No. They are sample formats only. They show the structure of USPS tracking numbers, not real packages.

Sources

• USPS Tracking: service and sample numbers
• USPS Tracking: service and sample numbers
• USPS FAQ: how to find your tracking number
• USPS FAQ: tracking basics
• U.S. Postal Inspection Service: smishing package tracking text scams