Placeholders for format in address form

Question

I am creating an address form and want to add placeholders to the fields to display the format of what the user needs to enter.

For email addresses, phone numbers and credit card details this is pretty standard but as a company with a mainly but not exclusive UK customer base, are there any downsides to using information for the placeholders aimed more at UK addresses.

For example -

Postcode/Zip Code: AB12 CD3 instead of Postcode/Zip Code: NY 10118

I know that placeholders for address forms is quite common place but is there a case for not including if you have an international customer base?

Answer 1

If you include a format guide, you should be sure that the format applies for your customers. If you have international customers for whom a UK postcode format will not apply, you run the very real risk of confusing them.

You could always ask for country first, and then present the format that would apply for that country. However that is a lot of development overhead and maintenance, and for most applications the cost will outweigh the benefit.

Most times I would stick to a generic guide that will work in all (or most) countries, or if that is not possible, simply leave it out.

Post codes vary greatly by country, and may people are not aware of the code structure for countries they are not from. The same applies to other aspects of addresses, so there it is usually best to leave the address as a free form text area with only the country field specified.