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ZIP Code Frequently Asked Questions

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Frequently Asked Questions

  1. What methods of payment do you accept?
  2. Do you accept purchase orders?
  3. What format does the database come in?
  4. How do I get the monthly database updates?
  5. Will a CD be mailed to me? How do I get the database?
  6. What happens after my 1 year subscription?
  7. How much does it cost to renew?
  8. Do you include ZIP Codes for the entire United States?
  9. Why do some ZIP Codes only have 3 or 4 digits in Excel?
  10. How often do you update the database?
  11. How current is the data?
  12. What are the sources of the data?
  13. How accurate is the data?
  14. Do you have any other countries besides the U.S.?
  15. How long does it take to get the data?
  16. Can I automate the database delivery?
  17. Do ZIP Codes change often?
  18. Do you support Military APO/FPO/DPO ZIP Codes?
  19. Do you have DMA information?
  20. How long have you been in business?
  21. What separates you from your competitors?

Why trust our ZIP Code Database?

100% Money Back Guarantee

A lot of companies make claims that they are the best but we truly feel no other ZIP Code provider provides nearly the quality of data and support as we do. We've been in operation since 2003 and have an extensive customer list of fortune 500 companies, individuals and small businesses. We also answer our phones. Seriously, we do not hide. Call us at 1-800-425-1169. was the first to offer an unconditional money back guarantee because we know our ZIP Code Database quality is superior. We are not just licensees of the USPS, we work directly with them and they license data back from us. We also work directly with other data vendors such as Pitney Bowes. Quality and service are our #1 priorities. But do not just trust us. See why you should choose us.

Does your ZIP Code Database contain ZCTAs?

No. To explain, you must understand what a ZCTA is. ZIP Code Tabulation Areas (ZCTAs) are generalized area representations of United States Postal Service (USPS) ZIP Code service areas. ZIP Codes are not true areas, but rather a collection of mail delivery routes. They exist solely for the expedient delivery of mail and they change as the needs of the USPS change. Most people think of ZIP Codes as a stable geographic area, but they are not. The U.S. Census aggregates data based on defined geographic regions and cannot use true ZIP Codes as a geographic entity. Thus, ZCTAs were created to differentiate between the U.S. Census region and the USPS true ZIP Code area. They are only changed every 10 years (with a new decennial census release) and diverge from the true ZIP Code area over time.

Many companies will use ZCTA data released by the U.S. Census and claim it as the true ZIP Code Area. They will do this and claim "it's close enough for most needs". takes data quality seriously, and "close enough" is not good enough. We license the true updated ZIP Code data directly from the USPS and always have the true ZIP Code Boundaries as the changes are made. Some data fields, such as Census Population data, are only available at the ZIP Code Tabulation Area, but these will always be clearly labeled as such.

What Formats are your ZIP Code Database in?

The ZIP Code Database comes in 4 different file types, all of which are made available to you immediately after purchase. You can download the ZIP Code Database in Access, Excel, CSV, and SQL for quick and easy importing into anything you need. For SQL, all table creation scripts are already prepared for you. You can download the database in all formats as many times as needed throughout your subscription. Our ZIP Code radius Finder application and industry leading technical support as also included at no charge.

We also provide FTP Access (free) for you to automate the delivery of the database every month as well as a ZIP Code API (separate license) for programmatic access.

Pie Chart showing break down of the different ZIP Code types.

How many types of ZIP Codes are there?

The U.S. Postal Service maintains 4 distinct types of ZIP Codes, known by their Classification Code:

  • <BLANK>: General. Used for general mail delivery.
  • P: P.O. Box. Used for mail deliveries to contract mail boxes only.
  • U: Unique. Used for large volumes of mail. Ex: Bank of America, Berkeley, IRS.
  • M: APO/FPO Military. Used for mail to service men and women stationed overseas.

The ZIP Code Database contains a 'Classification Code' column indicating each ZIP Code type by its letter. This allows you to select only the exact ZIP Code types you need or check if a provided ZIP Code has special limitations (most companies cannot ship to Military ZIP Codes).

ZIP Codes are not Geographic Divisions

Most people think of ZIP Codes as the last piece in geographic divisions: Nation > State > County > City > ZIP Code. This is not true. ZIP Codes were created exclusively for the expedient delivery of mail with mail routes designed to best suit the needs of the USPS. ZIP Codes do not always adhere to national or local geographic boundaries and limits.

ZIP Codes are not required to observe City, County, or State boundaries when those boundaries interfere with a mail carriers route. To put it in perspective, imagine being a postal employee placing mail in mailboxes down a long street. It would be highly inconvenient to stop and turn around due to an imaginary line.

ZIP Codes are Not Cities

Los Angeles city boundary vs Venice neighborhood boundary vs ZIP Code 90291 boundary

ZIP Codes have nothing to do with cities. While a ZIP Code has a city name, it is to reference the area it serves. A ZIP Code may also have names for other towns, villages, or well known neighborhoods. For example, ZIP Code 90291 is for Venice, CA. Venice is a residential, commercial, and recreational neighborhood with a statistically significant population of over 28,000 and located within the city limits of Los Angeles, CA. Even the ZIP Code boundary for 90291 does not match the neighborhood boundary for Venice, CA that is generally accepted. It is not possible to compare data for ZIP Code cities with data compiled at the city municipality level, because the boundaries that constrain each are very different.

The map to the left illustrates the disparity between boundaries. Los Angeles City Limits are shown in gray, the Venice Neighborhood Boundary in green outline, and the 90291 ZIP Code Boundary in red.

ZIP Codes that exist outside of city limits will likely have a city name of the larger area that it serves. Towns, Villages, and other well known places might be placed in the City Alias column for identification. Each record has a "MailingName" column that indicates if this name is acceptable for mailing purposes.

Do ZIP Codes Cross County Lines?

Yes. In fact, over 20% of all ZIP Codes cross county boundaries. Our ZIP Code Database indicates this with the 'Multi County' column. Any ZIP Code marked with a Y value indicates that it covers more than one county. The Business version offers a separate table detailing all counties a ZIP Code covers. The 'primary' county assigned to each ZIP Code is usually based on the part that receives the highest volume of mail. ZIP Codes cross state lines as well if needed, but this is much rarer. As with cities, you cannot compare data for ZIP Codes in a County with County data because the boundaries for each do not match.

What information is included in the Census American Community Survey?

The Census American Community Survey data in our Business Database includes over 500 fields of data taken from multiple topics including: Education, Households, Marital Status, Employment Status, Occupation, Housing Occupancy, Sex and Age, Race, and Voting Age.

The American Community Survey (ACS) is an ongoing survey that provides data every year -- giving communities the current information they need to plan investments and services. The ACS covers a broad range of topics about social, economic, demographic, and housing characteristics of the U.S. population.

This data is taken from the 2016-2020 5-Year estimates for each ZIP Code in tables DP02, DP03, DP04, and DP05. Included documentation details the fields available and information about how the data was collected. The 5-year estimates from the ACS are "period" estimates that represent data collected over a period of time. The primary advantage of using multiyear estimates is the increased statistical reliability of the data for less populated areas and small population subgroups.

Why is this ZIP Code not listed in your database?

"Why is this ZIP Code not listed in your database? We found it in some website or a customer reports it as being valid." We get this question quite frequently and every instance is investigated to be 100% sure. But the answer is nearly the same every time. This ZIP Code is no longer valid. Perhaps it was at one time, but it is no longer an active ZIP Code. The USPS is constantly changing ZIP Codes to match their current delivery needs. is a licensed distributor of the USPS and receives monthly updates from the USPS. Other websites do not adhere to the same data quality standards we do. Customers may have had a ZIP Code at one time but missed the notification that it has changed.

If you feel a ZIP Code is valid but not listed on our database, you can use the USPS "Lookup a ZIP Code" to check for yourself at If the USPS reports it as invalid and you believe this is an error, please contact us and we will research it.

Why aren't ethnicity populations adding up to the total population for the ZIP Code?

From 1790 to 1950, Census takers themselves determined the race of the Americans they were counting. Those Census takers used their own rules and perceptions to classify Americans into the single racial category they deemed appropriate. Obviously, there were flaws in this approach. Beginning with the 1960 Census, Americans were allowed to choose their own race. There were further changes in the 2000 Census, Americans had the ability to identify with more than one race entirely. The 2010 Census alone had 63 possible race categories. 6 for individual races and 57 for combined races. Over 9 million Americans chose more than one racial category in 2010 alone which was 2.9% of the population.

Because of the multi-racial identification aspect to the Census, the sum of the ethnicities will not equal the total population for a ZIP Code. A person can only be counted once for the total population. If that individual then selected both White and African American, they would then be counted once for each ethnicity. Since the person claiming multiple races is counted twice in the individual racial categories, they would then be counted twice when adding the races together for a sum total. This would not match the actual population due to its counting of that individual only once. The same sum issue applies to all levels of census data (City, County, State).

To learn more about the Census and the Race/Ethnicity questions, please visit

When I add up all of the population in the database, why doesn't it match the total on the Census website?

When you add up the populations for all ZIP Codes, it will not match the national population count. This effect is known and has many reasons why. The primary issue with this method of comparing data is that not everyone lives in a ZIP Code. ZIP Codes are created for the expediate delivery of mail. If a person lives 20 miles from a USPS location in rough terrain, the USPS will not deliver mail to them. The person would essentially live in no ZIP Code at all. The population sum at the ZIP Code level would not count these individuals, but they still exist. Higher demographics levels would be able to include this individual however, such as County and State summary levels.

Another factor affecting the ZIP Code population sum is that the Census does not count incarcerated individuals nor those in nursing homes. These people exist and are counted in population summaries at the County and State level, but they are not always residents of that explicit ZIP Code.

Q. What methods of payment do you accept?

A. We accept Visa, Mastercard, American Express, and PayPal for immediate download. You can also place your order choosing Mail In Check or Purchase Order but you will be unable to download the database until your payment is received.

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Q. Do you accept purchase orders?

A. Yes, we can accept purchase orders. Simply go through the order process as normal. When you come to the payment screen, choose Purchase Order as the payment type and complete your order. You can then print out a purchase order and mail in the payment. Once payment is received, access to download the database will be turned on.

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Q. What format does the database come in?

A. Our US ZIP Code Database is provided in three (4) formats: Microsoft® Access [.MDB], Microsoft® Excel [.XLS], ASCII Comma Delimited [.CSV], and a SQL Formatted File (.SQL).

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Q. How do I get the monthly database updates?

A. When you purchase, you setup a username and password. Each month, we will notify you via email that an updated database is available. Visit our site and login using your username and password. The updated databases will be available for download in any format we provide as well as a transactional log file with just the changes only.

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Q. Will a CD be mailed to me? How do I get the database?

A. No, our US ZIP Code Database is not mailed to you on CD. Once your order is completed, you will be able to download immediately. All monthly updates are also provided for online download. This ensures fastest delivery as the database is updated each month.

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Q. What happens after my 1 year subscription?

A. When your ZIP Code Database subscription is expiring, we will notify you by email 30, 10, and 1 day in advance. You can choose to renew at the current rate, or let your subscription expire. You can continue to use the database after your subscription has expired, but if you don't renew, you won't continue to get monthly updates.

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Q. How much does it cost to renew?

A. Currently, renewal prices are the same as the original purchase price.

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Q. Do you include ZIP Codes for the entire United States?

A. Yes. ZIP Code data is provided for all 50 U.S. States, Washington DC, Puerto Rico, Virgin Islands, Guam, and APO/FPO Military ZIP Codes.

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Q. Why do some ZIP Codes only have 3 or 4 digits in Excel?

A. Several ZIP Codes start 0 or 00. Excel interprets the column as numeric data, therefore it removes all preceding zeros. The data is good, it is simply Excel formatting the output. To correct this, open the spreadsheet. Highlight the column by clicking on "A" above the ZIP Code Label. From the menu at the top of the application, choose "Format" and then "Cells". On the popup window, choose "Special" from the "Number Tab" section, and then choose "ZIP Code" to the right. Click "OK". The ZIP Codes should now be formatted properly.

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Q. How often do you update the database?

A. Our ZIP Code Database is updated every month.

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Q. How current is the data?

A. Our ZIP Code Database is updated every month. the data is current as of June, 2023

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Q. What are the sources of the data?

A. Our ZIP Code Database is licensed and compiled from various sources. Postal and Delivery data comes from the USPS, Demographic data from the US Census, Statistical Areas from the OMB (Office of Management & Budget), private data sources, and some are computed by

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Q. How accurate is the data?

A. Accurate data is critical to the success of your business and ours. implements a very rigorous set of data integrity checks to ensure our database is as accurate as possible. In the unlikely event that a portion of data is confirmed as inaccurate, we will correct it within 2 business days. Our Free ZIP Code Database offers the same precise data, but with shortened Latitude/Longitude values.

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Q. Do you have any other countries besides the U.S.?

A. Yes. We also have the Canadian Postal Code Database.

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Q. How long does it take to get the data?

A. Instantly. As soon as your order is confirmed and payment is received, you can download the database.

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Q. Can I automate the database delivery?

A. Yes! Please email us requesting an FTP Account be setup for you to use in automating your processes. Please include your username or order number for reference. We will have it up and running within 1 hour.

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Q. Do ZIP Codes change often?

A. ZIP Code data changes frequently. Every year there are thousands of changes to the USPS ZIP Code records. Cities are added and removed. ZIP Codes are created or discontinued. Corrections are made. Boundaries change. Streets are added and street names change. Within a short time period, the database will be outdated if you do not download it every month.

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Q. Do you sport Military APO/FPO/DPO ZIP Codes??

A. Yes! Overseas military post offices operated or supported by the Army or Air Force use the city abbreviation APO [Army Post Office / Air (Force) Post Office], while overseas military post offices operated or supported by the Navy, Marine Corps or U.S. Coast Guard use the city abbreviation FPO (Fleet Post Office). Recently, the Department of State has begun establishing a semi-independent overseas postal system. Their city abbreviation is DPO. As of March 2009, less than 10 U.S. Embassy locations are known as DPOs. The other approximately 90 overseas U.S. embassy post offices fall under the management oversight of the military services and so are known as either as APOs or FPOs. Three quasi-state codes have been assigned depending on the (approximate) geographic location of the military mail recipient and also the carrier route to be taken. They are:

  • AE (Armed Forces Europe / Canada / Middle East / Africa) - 09XXX
  • AP (Armed Forces Pacific) - 962XX through 966XX
  • AA (Armed Forces Americas [excluding domestic and Canada]) - 340XX

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Q. Do you have DMA information?

A. No, Nielsen is the provider of that data and they do not allow others to redistribute it. If you need it, you need to go directly to them to get it at

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Q. How long have you been in business?

A. We have been selling our databases online since 2003 and have become the most trusted source of ZIP Code data.

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Q. What separates you from your competitors?

A. What separates us from our competitors is our level of customer service. We are here every day and we answer the phones during business hours. If you have a question or problem, we are here to help you. Additionally, we provide the most comprehensive database at the most competitive price. Our competition doesn't even come close. Try calling them! Also, our rigorous data integrity checks make our data the most accurate you can purchase.

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Portions of data provided by and © United States Postal Service 2023. is a non-exclusive licensee of the United States Postal Service.