Does USPS Reuse Tracking Numbers? (All You Need To Know)

While numbers are infinite, the combinations of numbers any shipping company can come up with when it comes to tracking are not.

This is likely because of their own self-imposed constraints; for example, the United States Postal Service uses a 22-digit series that may start with 9400, 9205, 9407, and so on.

It begs the question: Does USPS reuse tracking numbers? You might have experienced something to make you believe so. Well, here is your definitive answer!

Does USPS Reuse Tracking Numbers?

The United States Postal Service does reuse tracking numbers regularly. Due to the high volume of tracking numbers, it is unlikely anyone would repeat for the same customer, but the reuse of numbers has caused customers to receive new shipment updates on packages delivered to them years ago.

To learn more about why USPS reuses tracking numbers, how often they get thrown back into the mix, and for how long USPS keeps tracking information, plus more, here is all you need to know below!

Why Does USPS Reuse Tracking Numbers?

As I mentioned in the introduction, despite the seemingly infinite number of tracking combinations, shippers like USPS are actually somewhat limited.

This is because they can’t just use any combination of numbers that they want; USPS has to differentiate tracking numbers from UPS and FedEx (and they have to do the same).

USPS numbers tend to be 22 digits long and start with 9. The first four digits relate to the shipping service being used.

According to, these are some of the most popular:

USPS Tracking: 9400 1000 0000 0000 0000 00
Priority Mail: 9205 5000 0000 0000 0000 00
Certified Mail: 9407 3000 0000 0000 0000 00
Registered Mail: 9208 8000 0000 0000 0000 00
Signature Confirmation: 9202 1000 0000 0000 0000 00

As you can see, USPS really only has 18 digits to work with; that right there limits the number of possible combinations.

Then you must factor in the sheer volume of packages with Tracking that USPS handles year in and year out.

Actually, the number of packages USPS delivered during the winter holiday season per day was astonishing: 20 million. Per day!

With that many parcels crisscrossing the country, I would argue the vast majority of them are Tracking-enabled; it’s no wonder USPS has to recycle numbers at times.

How Often Are USPS Tracking Numbers Reused?

How Often Are USPS Tracking Numbers Reused?

While USPS hasn’t made any official statements about how often their tracking numbers are reused, I have found some anecdotal evidence that allows me to make an educated guess.

First, USPS holds onto your tracking information for you for up to 120 days or about four months.

After that time, the agency pretty much considers their end of the shipping bargain done, so they probably put the tracking number either back into rotation or back into line to be used.

One message thread on Etsy discussed the practice, with MaynardMillinery commenting: “I think a number drops off its previous record around six months post-shipment…”

This was in response to the original poster, who reported that a customer had received a delivery notification – less than a year after she had actually received her order.

Something similar was reported on a Reddit thread, where a tracking number for a December 2020 shipment was showing information for a delivery in August 2020.

It appears that tracking numbers can end up back in the system in less than a year.

What should you do if your tracking number has its “previous life” still attached?

Chances are, the label with the number has been created for your parcel, but the new shipment hasn’t been scanned/attached to it yet.

All you can do is wait for USPS to catch up, which they should do within days. Keep checking on your Tracking info each day.

If, for some reason, it never updates, this is an issue for the seller. Reach out to them so they can contact USPS about the matter.

How Long Does USPS Keep Tracking Information?

USPS Tracking, as a basic service, stores your tracking information for up to 120 days. Signature Confirmation is stored for up to one year.

Priority Mail Express, Certified Mail, Registered Mail, Numbered International Mail, and Adult Signature Required services all hold onto their tracking information for up to two years.

If you’re a seller with a generous return window, it might behoove you to screenshot the delivery confirmations of your sent packages.

If that tracking information disappears and you have a buyer who wants to belatedly dispute their purchase arrival, you’re out of luck.

(This happened to an eBay seller, who ended up losing their case to the buyer!)

If you don’t mind spending a little extra on your shipments, you can also purchase the USPS Tracking Plus tool.

This tool extends the amount of time you can access your Tracking information for up to 10 years.

However, the prices are per package; they start at $2.10 for six months and climb up to $9.99 or $12.99 for 10 years.

If you can afford it, it can certainly give you some peace of mind as a shipper that important tracking information won’t disappear when you need it.

To know more, you can also read our posts on whether or not USPS updates tracking, if USPS first class has tracking, and if USPS sends text messages. You may also be interested to find out if USPS prints labels

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Marques Thomas

Marques Thomas graduated with a MBA in 2011. Since then, Marques has worked in the retail and consumer service industry as a manager, advisor, and marketer. Marques is also the head writer and founder of

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