What methods can I use to aid users to remember a serial number? While you might expect people to write them down, many just try and remember them, then get it wrong, and need to retrieve the number again, reflecting badly on the overall experience of the system.

Environment. Users install software on their machine, which generates a unique serial number, eg SHD5E. We need them to remember this number for later entry into a website. Users typically wish to be anonymous, and we might not be connected to the internet.

Edit: they are entering the serial number on a completely different machine, such as generating serial numbers on factory floor and then entering them on office monitoring system later. The serial number is the key to allow office system to retrieve information generated by first machines.

If we make the serial numbers longer to encourage writing down, users make mistakes and get frustrated. We tried using a QR code with serial number, but not all users could use them.

We also thought about somehow converting the serial number to a rememberable phrase, such as "yellow dog 12", but this needs a few hundred useable words in or to keep it short, (spelling alphabet? Not just phonetic alphabet) and I dont trust myself to create a good list of words for this purpose.

  • 1
    Group the digits into 3 or 4 digit chunks like a credit cards and phone numbers.
    – obelia
    Oct 25, 2013 at 22:38
  • You needn't reinvent the generation of rather unique, rememberable phrases. Consider a password generator that worked this out. Oct 26, 2013 at 9:59

5 Answers 5


Rather than a serial number, which regardless of how easy or short it is, is very machine like, binary and non-human. Applying some simple NLP techniques, if you give the user more "English based" words to remember (the more abstract the better), the chances are they will recall this phrase easier. I wonder if your system could generate an adjective, a noun, and a number system?

For instance, a system generating SH5D3S is machine, binary like. Easily forgotten.

A system that generates, "7 angry monkeys", is much more memorable. It creates a mental image for the customer that is much easier to recall than a random set of digits.

Agreed it does require a change to the key generation, but possibly a way forward?

A test? In a couple days... I bet you still remember 7 angry monkeys.


You might want to take advantage of chunking: http://en.wikipedia.org/wiki/Chunking_(psychology) A series of pronounceable letter groups (even if they're not necessarily real words) is much easier to remember than a series of numbers and letters of equivalent length.

But asking users to remember or write down a serial code seems like a design smell. You can't rely on human memory as a part of your user experience, especially if the user didn't create the code themselves. So the real question is why you're presenting this user with a serial number so long before they actually need it. Shouldn't they be able to open up your app when visiting the website, copy the serial code, and paste it into their browser? You could even create a browser extension that automates that process.

Edit: Just saw your comment that the code is generated on a different machine... disregard that last paragraph.

  • thanx for reference to chunking and research, was interesting. Unfortunately I can only accept one answer, but combing chunking and 'abstract phrases' might fit our needs
    – rlb
    Oct 31, 2013 at 9:03

You could make the serial number a link that passes itself to the web site automatically.

  • Unfortunately, we need the serial number entered on a different system to the one generating the number. Ie you install on "A" and enter the serial number on "B". Also, many of the systems do not have direct internet connection.
    – rlb
    Oct 25, 2013 at 22:00

Just make it short enough to be fairly easily remembered (SHD5E is fine), and tell the user to write it down so they can enter it later. Or — or preferably and — have the software they install generate the serial number at will (eg via Help > About), like this Adobe modal dialog which I've doctored slightly. That way they don't have to remember the number, or at least can easily recover it.

Example serial number dialog

I don't understand how you expect users to enter the number into a website if either you or they are not connected to the internet.


Some options are:

  1. Generate key file, which should be transfered to the target machine (via flash drive, etc.).
    .+ No remembering needed
    .+ Key can be more complex
    .- Flash drive needed
  2. User generated key. Propose user to participate in generating key. So, for example, system generate a part of a key, say DOG and proposes a user to enter second part (somebody enters LED ZEPPELIN, as they has BLACK DOG song, other person could enter BUZ for other reason). This way uses associative memory, which is more realible than random key.
    .+ More easy to remember
    .- Cannot guarantee uniqueness
    .- Still could be forgotten

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.