One of the most common potential areas of friction within e-commerce checkouts is problems with postcode entry. 

The trouble is, people will enter their postcodes in a number of different ways, in upper or lower case, with or without a space in the middle, or will some make common errors.

If websites are too rigid in their acceptance of postcodes and unclear in their error messages, then this can be a real source of frustration for potential customers. 

The postcode problem

I’m fairly haphazard when entering postcodes, sometimes I leave a space in the middle of the code, sometimes I don’t. That’s just how I roll;)

I’m sure I’m not the only one, and many sites do account for this habit, and will accept postcodes with or without a space, which is how it should be done. 

However, some don’t, and entering your postcode in the ‘wrong’ format will trigger an error message.

I encountered this recently on Tesco Clothing. In this case I was too lazy to add the space: 


There are several problems here: 

  • The first is the fact that I have an error message. These are to be avoided at all costs. Error messages are annoying, especially if the customer hasn’t really done anything wrong. 
  • Secondly, the checkout form does not specify the format I need to use. This could be indicated with a simple sentence, or by splitting into two fields so that it’s clear a gap is needed. 
  • The error message in this case does nothing to address the issue. It doesn’t tell me what I’ve done wrong, or how I can correct it. I’m left to guess the reason, which is not good enough.
  • It’s possible that some users may think their postcode is incorrect, check it, re-enter and encounter the same error again. Either they’ll figure it out in the end, or they’ll just abandon the process. Either way, it’s an unnecessary barrier for shoppers. 

It is not difficult to add or remove spaces from a postcode (or indeed a telephone number), so why blame the customer when you didn’t even tell them what you wanted in the first place? 

According to Lovehoney Head of E-commerce Matthew Curry: 

It’s pretty easy to code around the spacing issue. All postcodes have to have three alphanumerics after the space (whether it exists or not), so you can figure out what the outcode part of what’s been entered, and correctly format the input before passing it to whatever postcode validator you have. Remember though that some new addresses may not be in the database of your postcode validator, so always provide a manual override.

What should retailers do? 

The rule here is to let customers type in what they want and then use your e-commerce system to process it into a different format if necessary.

If the customer does make an error during checkout it must be made clear that an error has been detected and secondly, the location of the error on the form must be highlighted and the nature of the error indicated.

Other postcode issues

This is not the only potential problem with postcode entry, though it is perhaps the most common, and also easiest to fix. 

There are other possible issues around customers entering the letter ‘O’ when a zero was required, the number 1 instead of the letter ‘i’ or shifted characters (i.e. £ instead of 3, $ rather than 4). 

All of these issues can potentially produce error messages, and in many cases customers may be unaware of their mistake. This frustration, often compounded by unclear error messages such as Tesco’s, can cause customers to abandon purchases.

For example, on Argos, if I type the letter O rather than a zero, it generates an error message. This happens with or without a space in the postcode. 

Argos is the second biggest online retailer in the UK, so I wonder how many customers may be abandoning due to this common error. 

These may seem small issues, but it can make a big difference to your sales. With the O/zero issue, Belron’s Craig Sullivan realised this was was causing 2.5% of customers to abandon and changed the checkout forms to anticipate this input error. 

It’s a simple and elegant fix which avoids blaming the customer and makes the checkout process that little bit smoother. 

Avoid the dreaded error message

The main point here is to avoid error messages as much as possible. Users will enter information in different ways, and will make mistakes. 

Many of these errors, like the ones described above, are common and easy to anticipate. By accounting for these mistakes, e-commerce sites can avoid the user frustration that my cause abandonment

Of course, customers will still find ways to make errors however much you account for them. In this case, make sure your error messaging is a)polite and b)instructive. 

This one (since removed) is instructive at least, but fails on point a. (HT:@danbarker):

The fewer error messages people see during the checkout process, the more likely it is that they will complete the purchase.