Given that many jurisdictions (including my own) don't use postal codes, should the ZIP/postal codes be mandatory on web-forms?

Additional info: I'm a web developer building ecommerce sites, and while some of the target customers may be in the U.S., many are not. Given development deadlines, I don't have time to code a complex solution.

Is it reasonable to assume that users will know if they have to input a postal code or not?


3 Answers 3


Create fields for all the main address components, including postal/zip codes, but don't make them mandatory or put restrictions on format.

People who are used to always including postal/zip codes will include it when they see the spot on the form. If this is a shipping address, and they actually want to receive their purchase, they are motivated to include the information!

In contrast, if they were just signing up for a web service, and you started asking for a full mailing address without explaining why they should give it to you, then people would be more likely to leave it off.

Your other options are:

  1. Create a database of all countries you might be shipping to, and which address fields are required for each, and adjust your form validation accordingly. This is what most major e-commerce sites do, but I think this is the "complex solution" that you didn't want to code.

  2. Make all fields required, and frustrate potential customers by telling them "postal code is required" when they don't have a postal code to enter. Not a good plan.

  3. Use a completely open-ended address field (Address line 1, Address line 2, etc.) and trust that people will know what is appropriate for their country. However, without prompting people to remember the different types of information, they are more likely to leave it out.


Web forms are at times a bugbear for users. The main problem they have is that they feel too much is asked in order for them to achieve their goal (in your case to contact the owner of a website).

My view is that, where possible, avoid asking users for information that is not required. Contextualise the request of ZIP code only if that information is used by the owner of that data.

Alternatively, you could put it among the fields of the form but not make it as a required field.

I hope that helps. Antonio

  • The info is required for a shipping address. My question is about whether the ZIP/postal code field in the form should be mandatory or optional, given that many countries don't use them. Can we trust the users to validate the form themselves? Nov 11, 2014 at 17:03
  • If it is required to allow the customers to receive the good purchased then make it mandatory - I go with the assumption that, like you said, finding a solution that validate the address automatically is time consuming and expensive.
    – Taritaro
    Nov 11, 2014 at 17:10
  • @Taritaro: I don't quite understand that reasoning: Wouldn't making the ZIP code mandatory in the form make ordering impossible for users who do not have a ZIP code? Nov 12, 2014 at 9:49
  • I am not sure about the US, but in Europe (UK, Italy and Belgium for instance) a postcode is mandatory information, so you have to know it and it is required. I came across this resource that perhaps can make the whole thing easier: bootstrapvalidator.com/validators/zipCode
    – Taritaro
    Nov 12, 2014 at 10:00
  • @Taritaro: The OP explicitly specified many of their customers are from a location that does not use ZIP codes. It is irrelevant whether they are required elsewhere, by making it mandatory, you prevent users that do not have a ZIP code (as it sounds in the question, a significant part of the customers of that site) from ordering. Nov 12, 2014 at 12:56

Since you are on a tight deadline and don't have time to properly implement the best solution then my advice would be to provide an additional field and label it "Additional Address info. (zip code, apt #, Attn. name, etc...)" so if it applies to the user then they will fill something in.

I am making this recommendation because you specified that most clients are not in the USA.

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