# Do you know your +4 Zip Code? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [July 10, 2012, 7:13pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821 "2012-07-10T19:13:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Gangster\_Octopus](https://avatars.discourse-cdn.com/v4/letter/g/a8b319/32.png) [@Gangster\_Octopus](https://boards.straightdope.com/u/Gangster_Octopus)\ **Post date:** [July 10, 2012, 7:13pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/1 "2012-07-10T19:13:46Z")
Do you know by heart what your +4 Zip Code is? I don’t know mine, except that it starts with an 8. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [July 10, 2012, 7:16pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/2 "2012-07-10T19:16:51Z")
If you don’t, [you can look it up here.](https://tools.usps.com/go/ZipLookupAction!input.action) Do you know your [DPB](http://en.wikipedia.org/wiki/Delivery_point) (Delivery Point Barcode)? That is 2 digits that follow the ZIP, ZIP+4 in the most extensive barcodes. Rarely printed, but they exist and are read by scanners. Your full address is ZZZZZ-YYYY-XX, which brings it down to a single box or slot. Usually the DP is the last 2 digits of an address, e.g., if your address is 1234 Fake Street, your DP is 34. There are some exceptions. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [July 10, 2012, 7:52pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/3 "2012-07-10T19:52:24Z")
I know mine. I need to try an experiment where I just put the Zip+4+DPB on an envelope and see if it gets back to me. Would be worth the [del]25c[/del] [del]32c[/del] [del]36c[/del] [del]39c[/del] 45c. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [July 10, 2012, 7:54pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/4 "2012-07-10T19:54:08Z")
Yes. I’ve used it for a couple of decades. Some time ago, the post office gave me a directory of all Zip+4 in New York. Looking through it, you could find the addresses of some celebrities (I remember Isaac Asimov and Walter Cronkite) who got so much mail they had their own Zip+4. ---
**Author:** ![Procrustus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/procrustus/32/2994_2.png) [@Procrustus](https://boards.straightdope.com/u/Procrustus)\ **Post date:** [July 10, 2012, 7:56pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/5 "2012-07-10T19:56:36Z")
I would have to look at my incoming mail if I needed to use it, which I have never had to do ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [July 10, 2012, 8:01pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/6 "2012-07-10T20:01:56Z")
I do not. I did look it up, but I didn’t bother to do more than glance at it. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [July 10, 2012, 8:05pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/7 "2012-07-10T20:05:13Z")
> [@Procrustus](#): > > I would have to look at my incoming mail if I needed to use it, which I have never had to do You may be surprised to find that most of your incoming mail has it encoded in the barcode already, supplied by lookup software at the point of origin. Not only is the (ZIP, ZIP+4, DP) encoded, but there is also a single-digit checksum. But that was the old way, called [Postnet.](http://en.wikipedia.org/wiki/POSTNET) The machines still read it, although it has been superseded by [Intelligent Mail Barcode,](http://en.wikipedia.org/wiki/Intelligent_Mail_barcode) which encodes a lot more stuff than just 11-digit ZIP codes. It’s required on most bulk mail since May 2011. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [July 10, 2012, 8:31pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/8 "2012-07-10T20:31:42Z")
nm, misread something. ---
**Author:** ![Bernd\_Stromberg](https://avatars.discourse-cdn.com/v4/letter/b/ed8c4c/32.png) [@Bernd\_Stromberg](https://boards.straightdope.com/u/Bernd_Stromberg)\ **Post date:** [July 10, 2012, 8:40pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/9 "2012-07-10T20:40:19Z")
Those are citizen relocation codes. With any luck, we’ll … never need 'em. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [July 10, 2012, 8:53pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/10 "2012-07-10T20:53:08Z")
Yes, but only because it’s easy to remember, as it actually winds up being a repeat of the numbers in my main ZIP code. ---
**Author:** ![sevenwood](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@sevenwood](https://boards.straightdope.com/u/sevenwood)\ **Post date:** [July 10, 2012, 9:29pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/11 "2012-07-10T21:29:41Z")
I know mine (…1415). But I’ve stopped entering the full nine digits anywhere, as they don’t seem to make any difference in terms of items arriving. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [July 10, 2012, 9:57pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/12 "2012-07-10T21:57:51Z")
> [@sevenwood](#): > > I know mine (…1415). But I’ve stopped entering the full nine digits anywhere, as they don’t seem to make any difference in terms of items arriving. That’s probably because they are generated from address lookup software anyway, which needs only a street address, city, state, and 5-digit zip to look up the rest. I suspect that even if you put in a wrong ZIP+4, it would be overridden. ---
**Author:** ![kevja](https://avatars.discourse-cdn.com/v4/letter/k/aeb1de/32.png) [@kevja](https://boards.straightdope.com/u/kevja)\ **Post date:** [July 10, 2012, 10:11pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/13 "2012-07-10T22:11:19Z")
I’ve known mine since I moved into my apartment building 17 years ago. I’ve lived in my unit on the fifth floor for the past 16 years. The first year I was here, I was on the third floor. After I made the two floor move, I noticed the last number on the ZIP+4 code changed from three to four. It seemed amazing at the time. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [July 10, 2012, 10:13pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/14 "2012-07-10T22:13:03Z")
> [@kevja](#): > > After I made the two floor move, I noticed the last number on the ZIP+4 code changed from three to four. Not three to five? ---
**Author:** ![The\_Devil\_s\_Grandmother](https://avatars.discourse-cdn.com/v4/letter/t/74df32/32.png) [@The\_Devil\_s\_Grandmother](https://boards.straightdope.com/u/The_Devil_s_Grandmother)\ **Post date:** [July 10, 2012, 10:20pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/15 "2012-07-10T22:20:00Z")
I know mine and using it does seem to speed up USPS delived packages. No data, just a feeling. ---
**Author:** ![Angel\_of\_the\_Lord](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/angel_of_the_lord/32/2949_2.png) [@Angel\_of\_the\_Lord](https://boards.straightdope.com/u/Angel_of_the_Lord)\ **Post date:** [July 10, 2012, 11:30pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/16 "2012-07-10T23:30:43Z")
Yeah, but I also remember my calling card number from college, and phone numbers from 15 years ago that I only used a handful of times. Numbers almost never leave me. ---
**Author:** ![twickster](https://avatars.discourse-cdn.com/v4/letter/t/ec9cab/32.png) [@twickster](https://boards.straightdope.com/u/twickster)\ **Post date:** [July 10, 2012, 11:45pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/17 "2012-07-10T23:45:11Z")
Yes, but I’ve been living here more than 20 years. ---
**Author:** ![PapSett](https://avatars.discourse-cdn.com/v4/letter/p/ecc23a/32.png) [@PapSett](https://boards.straightdope.com/u/PapSett)\ **Post date:** [July 10, 2012, 11:45pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/18 "2012-07-10T23:45:40Z")
Yup. 3415. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [July 10, 2012, 11:47pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/19 "2012-07-10T23:47:40Z")
Yep. Not that hard - 4 numbers repeat. ---
**Author:** ![etv78](https://avatars.discourse-cdn.com/v4/letter/e/d78d45/32.png) [@etv78](https://boards.straightdope.com/u/etv78)\ **Post date:** [July 10, 2012, 11:57pm UTC](https://boards.straightdope.com/t/do-you-know-your-4-zip-code/627821/20 "2012-07-10T23:57:46Z")
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