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Checking the Accuracy of Your Address List

Why bother? First, because it's required by the Postal Service. Second, look at these statistics:

  • 17% of Americans change addresses annually.
  • 43 million people move each year.
  • One out of every six families move each year.

How many of these people are your customers or members?

Just because you buy or rent a list does not mean that the addresses are correct, checked, updated, or "certified." To make sure that you are getting a list with accurate addresses, ask about the National Deliverability Index (NDI) of the list. The NDI rates the percentage of addresses in a list that are deliverable. Use the NDI to target the address elements you need to get the delivery ó- and postage rate ó- you want. For example, if you are targeting a specific 5-digit ZIP Code, look for an NDI of 100% for address element.

To qualify for:

You must verify:

By this Date:

Presorted rates

5-digit ZIP Code 12 months of mailing

Automation rates

Complete addresses 180 days of mailing

Enhanced carrier route rates

Carrier route information 90 days of mailing


The Postal Service offers many ways to check the accuracy of your list. Vendors also offer USPS-approved products and services for address list maintenance.

To claim presorted Standard Mail and Presorted First-Class Mail rates, you MUST have checked the accuracy of ZIP Codes within the last 12 months. When you fill out and sign your postage statement, this is one of the standards that you are certifying your mailing meets to qualify for the rates claimed.

Your local post office or business mail entry staff can help you choose the best option for cleaning up your mailing list. Here are some of choices:

Use www.usps.com to check the ZIP Codes in your list.
Process your address list through CASS-certified software.
Address List Correction Service. You can submit a printout of your list to the Postal Service and we will mark any changes. There is a fee for this service. It is available through your Address Management System Office.
National Change of Address (NCOA). A licensed vendor will run your mailing list through special software that updates addresses for your customers who have filed a change-of-address with the post office. The advantage to using NCOA is that you clean up your list BEFORE you mail. You also know in advance how much itís going to cost you (because a vendor charges by the address). With an ancillary service endorsement you get the same result (a corrected address) AFTER you mail, and you don't know how much you'll pay in fees until AFTER the corrections come back.
Look up the ZIP Codes in Publication 65, ZIP Code Directory. This hard copy book is available at your local post office.
Move Update is required for all presorted First-Class mailings. A USPS-approved method must be used within 6 months of the date of mailing. National Change of Address includes Move Update. Using NCOA satisfies the Move Update requirement.

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