What are fun postcodes to use when testing?

This is a lengthy transfer of the highlights from a post originally posted by @sheymouse on the old Software Testing Club. The intention of the post was to compile a list of fun postcodes (from any country) which can be used when testing, and give a little spark of fun or interest. If I’ve mis-tagged or missed anyone, I apologise!

Original Thread

@sheymouse started off with some postcodes he uses regularly:

  • W1J 7NT - 149 Piccadilly, London. House of the Duke of Wellington
  • DE12 8HJ - 17 Burton Road Coton in the Elms, Derbyshire. The Black Horse Pub, possibly the furthest pub from the sea in the UK.
  • SW1A 1AA - Buckingham Palace

Stephen Hill added
One of the most common mistakes people make is to assume a Postcode covers at most one street: HD7 5UZ covers 7.

  • HD7 5UZ - covers 7 streets; the most in the UK
  • CH5 3QW - the longest addresses in terms of numbers of elements
  • Anywhere in SA63 - the Post Town is CLARBESTON ROAD
  • W2 1JB - When all the premises get expanded you’ll get the longest ‘premise string’ in the UK
  • PL7 1RF - Devon and Cornwall Police vs Devon and Cornwall Constabulary
  • GIR 0AA - special case Postcode for Girobank at Bootle"

You will find that ‘towns and large villages’ are classed as Localities; Jersey; the Isle of Man and Guernsey are the Post Towns.

  • JE3 1EP
  • JE2 3XP
  • IM9 4EB
  • IM9 4AJ has no street
  • GY7 9YH

There is the strange case of the PO Box with no other identifying info at GY1 3EW

29, IV27 4EG is a horror story address for those of you interested in such things. The formatted postal address is as follows:

IV27 4EG

This arises from an anomaly in the way the data was originally entered on Royal Mail’s database because all the other premises at that Postcode have a building name of, for example, “15 Lochside”. I suspect that “Lochside” is actually a street but it is not on the data as such. It therefore follows that the ‘correct’ data for this record should be a building name of “29 Lochside” giving an address of:

29 Lochside
IV27 4EG.

I noticed that someone reference PL7 1RF above. There is another interesting point about that Postcode: there are two premises there for the Devon and Cornwall police. In the UK ‘Constabulary’ is another word for ‘Police force’. Therefore “Devon and Cornwall Police, PL7 1RF” is pretty ambiguous as it could refer to either of the following:

Devon & Cornwall Constabulary
4 Valley Road


Devon & Cornwall Police
8-10 Valley Road
PL7 1RF"

@lcrandall_98 posted
I tend to use the following quite a bit:

  • 68873 - St. Paul, Nebraska, population 1000 peeps give or take, 1500 if you include cows. My hometown!
  • 10001/10002/etc. - Manhattan, New York
  • Any of the Denver area zip codes (my current hometown!)
  • 92803 - Disneyland, Anaheim, California. The happiest place on earth!"

Phil Kirkham shared one you’d think wasn’t real “Hell, MI 48169”

@katepaulk added:

  • For US postcodes, any that start with 0 (because there’s a tendency to forget that these are valid)
  • 01111 (Hampden, Massachusetts)
  • I’ll also do the 5+4 format that identifies something to the house/PO box
  • 01111-1111 (I don’t actually know what house this is)
  • For anything that says it’s international, I’ll use as many different formats as I know of - Canadian postal codes, UK ones, Australian, NZ… As well as the home country of the site.

Emma P

  • PL7 1RF – Address list includes ‘&’ ‘(‘ ‘-‘
  • IM94AJ - no street
  • GY1 3EW – po box
  • CH5 3QW – high number of address elements

My previous life was as a Postcode Data Analyst so have a frightening affinity with Postcodes.

PAF is built from the posties on the ground observations, making it great test data as it contains all the weirdness of the real world, vanity addresses (“Welcome to Winter Towers”) businesses opening, closing, moving, growing, shrinking!

EC and WC (WC1A 1AA) postcodes often freak a lot of systems, as do single char areas (M, S etc).

Throw your non geographics in there. Data wise (their cartesian coordinates) they are locationally matched to the next level of Postcode above. So:

M1 1AA

would try and match to:

M1 1A


M1 1, M1, and M.

If it had no sub sector, sector, or district corresponding it would match coordinates to the Area!
I could go on, its all flooding back.
Don’t get me started on digitising the Postcode boundaries of the coast of Scotland. Or individually fixing AddressPoint. shudders

New Thread

This post was from 2012 originally. For a new thread, I’d ask of you: Do you have any that you’d add to the list? Are all of the above still good ones to use?

Ireland have since got Eircodes which are Irelands attempt at postcodes. I’ve heard these have caused mayhem. Has anyone had to test these yet? Are there any particularly sticky ones?


I tweeted about this a while ago, some ‘interesting’ ideas for test addresses (including postcodes/zip codes) in the replies:

See also the replies to:

Anyway, this led to me writing this blog post, which discusses what we could/should consider when using test data such as postcodes:

My personal favourite is the postcode for Downing Street (SW1A 2AA), which I suppose is similar to Buckingham Palace in that it’s a famous address but also not particularly atypical of a normal UK address in terms of how it looks written out.

Another category of post codes I didn’t see mentioned above are those for armed forces members living abroad - you can send post to them via the British Forces Post Office. The Wikipedia article gives the example of ‘BFPO 61’ which corresponds to Milan, Italy. if you specified the individual + company + regiment along with this then it would eventually be sent to that person (or a safe location nearby) wherever they happened to be stationed. The article goes on to say that UK-style postcodes starting with ‘BF1’ were introduced in 2012 to accomodate online systems that don’t support the BFPO format - ‘BF1 2AY’ would be the equivalent of ‘BFPO 61’ - the address is then translated back into BFPO format before it is sent abroad.


Back in 2016, when I was working for a facilities management company with operations across the whole British Isles, we addressed this issue for the new app we were working on and our resident expert said that Eircodes were still being rolled out and didn’t have 100% coverage. I shall have to ask some of my Irish contacts next time we speak.


To start with, any example from the address falsehoods list.

Australian postcodes 2001, 3001, 4001, 5001, 6001, 7001 (all of these are only valid for post office box numbers in the capital city post office - which may or may not be a GPO box rather than a standard PO box)

https://postcodes-australia.com/ also lists some that are designated for administrative use only.


I don’t work a lot with post codes (like… not at all), but here are a few things I have problems with at a somewhat regular basis:
The Dutch post codes are a series of 4 numbers followed by 2 letters, such as 7315 JA (Paleis het Loo, Apeldoorn).
The numbers refer to a region and the letters refer to a location within the region (such as a street), so 7315 refers to the area in Apeldoorn, while JA refers to Koninklijk Park.

Now the problems:
When visiting a weather app, one would expect the 4 numbers to be a valid input without the letters. This is not always the case.
Sometimes, inputing the full post code results in an error, because it only wants the numbers.
Sometimes, a blank space is expected between the numbers and the letters, sometimes it needs to be connected (such as 7315JA). (Another test case, which will rarely come up, would be to put a different character between the numbers and letters, such as 7315-JA)


Oh they’re supposed to have 100% coverage now but we got 5 unique eircodes for the 1 house last year and not 1 of them could actually find the house. (Seriously the house is not big enough to cover 5 postal code areas). A helpful DPD driver gave us one he was able to get from his handheld based on his location when delivering one day which seems to work fine.


And I assume that particular code didn’t match any of the five “official” ones. :grinning:


Oh of course it didn’t! The 5 official ones didn’t find any addresses :joy:

1 Like

UK postcodes aren’t always 100% right, either. Back when I was freelancing as an estate agent’s photographer, I was directed to a property which turned out to be derelict. The property I was supposed to be photographing was a quarter-mile down the road and the owner complained that this was always happening.

1 Like

Don’t forget other countries, too. Canada is fairly straight forward with all codes being in the format of alternating letters and numbers: A1A 1A1 (the space is used when writing by hand but often stripped out electronically). Santa Claus has a postal code which is actually used to send letters and get a response from Santa (or volunteers at the Canadian post office): H0H 0H0
The full address is:
Santa Claus
North Pole
You probably need to add “Canada” at the bottom if sending from another country. Also, I’m not sure if the Canadian postal service will send international responses.

USA postal codes are 5 numbers (for an area), and optionally 5 numbers followed by a dash and 4 numbers for a specific address: 10014 or 10014-1342

Try entering a valid postal code and then change the country. See what disappears and what stays. IMHO the address lines and city should stay and the state/province and postal code should be removed to be re-entered and checked for that country (but people rarely ask me for my humble opinion :slightly_smiling_face: )


Oddly enough, when I used to test an ecommerce site, we often used the US airbase in Aviano, Italy, for a test. (09603, IIRC.)


This is my source of inspiration :3.

Presentation gives nice overview

Under specials
There are few post codes for Santa ^^


I like to see if there is a language or parental filter so i use KW17 2LN, not sure what they call the residents ?
or the best place to live BH20 7HU
i also use BFPOs


These days with the open plus codes freely available, I don’t know why we can’t include those in addresses too: it can also make it easier to locate where exactly the correct letterbox is!

NB Plus codes are like the “what 3 words” thing that had some internet fame a few years back but unlike them are not proprietary: https://plus.codes/


I can’t believe I forgot to add another fun Irish one:

Some Irish addresses will need to be able to accept phone numbers in the address line.


In certain areas, you can have many people called the same name living very close to each other e.g.
Mary Ward
Town name

With the history that Eircodes have here so far, the phone number included in the address is more likely to find the right Mary than the Eircode would so make sure you allow numbers & symbols in your address entry :stuck_out_tongue:


Love this post. I use random generated postcodes and names in a previous role and set famous people in postcodes they wouldn’t otherwise live at, :joy:


I also have found postcode CV4 7AL as has 5000 addresses and most address api services now restrict to max 100 results


Welcome on board Jim. Was up your neck of the woods in the summer to escape that super hot week we had in England. This one is totally gold! Love the avatar too, too bad I have forgotten my Mojang account password.

1 Like

Hi Conrad

Thanks for the welcome, I do want to be more active in the community.

I found this was a good source when testing our address api (postcode lookup)


Always good to find new sources of information coming from folk and makes me wonder how many test engineer online websites there are out there which know about these cool gems. I’m mainly camping this thread because at some point I want to apply myself to creating a simple test dataset generator. I keep skilling up on programming on weekends with little automation projects, and this has been a looming one to get into.

I just don’t have much experience with customer capture, so @jimbob if you have some horror stories on the whole address checking topic, please do share.