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A Guide to Error Messages in Online Forms

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We all make mistakes from time to time when completing forms, for a variety of reasons. Forms are an obstacle to overcome before we get to what we really want, be that to purchase something, sign up for a mailing list or register an interest in a service, so we often rush them and make careless mistakes along the way - for example, I might type “tomf@ormisimoc.om” instead of “tom@formisimo.com”. User errors like this are unavoidable.

Less unavoidable are errors caused by:

Some fields by their very nature are more prone to users making mistakes. They tend to be fields asking for information that a user may not have memorised, is more complex, or can be given in more than one format:

Date fields - if you’re using a free text field (instead of a drop down) - do you allow US users to enter the month first, and should the year be entered as two characters, or four?

Phone numbers – Do you allow international dialing codes (+44), brackets around area codes, or even simply spaces within the number?

Credit card/bank details – do you allow users to enter spaces so the numbers so they can reflect how they appear on a physical card?

Password fields - we’ve spoken about this elsewhere, but these tend to be hard to get right the first time.

So, if you understand that user mistakes are inevitable, how can you best help users correct their mistakes and submit your form successfully? With error messages of course, but how best to implement them?


Error messages should be clearly indicated

When a user makes a mistake, you should let them know. And you should be clear where that error has been made. You can do this by:

These sounds fairly intuitive, but many forms fail to get these basics right.

For example, if you are listing the mistakes made at the top of the form (as a summary that one or more mistakes have been made and drawing attention to this fact), do not think that this means you should not also highlight the fields in question.

For example, in this form, the errors are listed at the top of the form:



But the fields themselves contain no visual cue that the error applies to that field - no highlight, no message next to the field.

In  the following form, the input itself has not been highlighted, a red cross has been added, but the error message text blends in with the other help text and labels on the form:


There is a risk here that a user would not identify the text as error message text and simply not read it, assuming it had been there the whole time.

Compare the above with the following:


The field is highlighted in red, and the error message displays next to the field in red, using italics to distinguish the error message from other text on the form.

Error messages should be unambiguous and helpful

So you’ve shown an error message next to the field in question - what should the message contain?

A good rule of thumb here is to try and emulate how you would help a person if you were sat next to them assisting them to complete the form. You would want to speak to them clearly, helpfully, and avoid jargon words. You would not assume the person was a developer, and yet error messages are often implemented in a way that seems more befitting of a computer than a human. For example:



Does this mean my name should have or be a numerical value? Should there be numbers at the end? Similarly, ‘valid’ is a word we talk about when designing error messages, but it not common parlance for regular folk in the world:



What does an invalid email address mean? What are the validation rules of which you speak?

Some words then to avoid if possible:

Value, invalid, error, required

So messages like the following are better:






Or this:



Or this multi-message approach to guiding a user through entering an email address:




Special points go to this form, which also suggests a potential fix to a possible error:




If you do include some of those jargon words, ensure there is more information contained within the error message - guide them to get it right, not just show where they got it wrong.

Mistakes may be inevitable, but your error messages should help users get it right the second time.

Users should not  have to memorize the fix

Listing error messages at the top of a form can in some circumstances be beneficial. For example if you have a long form on a single page and do not have a top list, a user may miss some of the errors by scrolling past them. Having them listed, and a user taken to the top of the page encourages them to review the total number of errors, then work their way through them.

However, you must always display both the list and the errors next to the fields, otherwise you may find a situation where the user reviews the list at the top:




And then scrolls down to start the process of correcting them:


The messages are gone, and the user has to remember the mistake they made as well as any guidance as to the fix.

Equally, you want to keep any helpful ‘corrective’ information visible next to the field whilst a user is fixing the issue. If you make the error message disappear when a user returns to a field (but before they’ve fixed the issue), they may simply forget their exact mistake and have to try to submit the form again to make the error message pop up again.

However, you will want to remove the error as soon as possible. For example in this field:




I left the email field blank, then returned to it after seeing an error. Even after exiting the field, the message remains. I, as a user, might think that there is still some issue with my email. The first message can be removed as soon as I type any keys in the field, and the second can be removed as soon as the user focusses-out of the field.

For example in this form, the error messages disappear as I fix them:



Inline validation and errors are great

If you’d like to read an in depth article about the benefits of inline validation, you can find that here,but the TLDR is this:

“Inline validation can help users correct incorrectly formatted data as they progress through the form, hopefully resulting in less attempts to submit the form for a final time. However it should not be used as a bandage, as your ultimate goal should be to try and help users avoid mistakes in the first place, especially if their ‘mistakes’ are simply a result of your form being unnecessarily inflexible in the data it accepts.”

Which brings us nicely onto the next point:

Prevention is better than cure

You can’t talk about error messages without recognising that prevention is the best course of action. You want to try and reduce the number of avoidable mistakes people make, and you can do this with good form design.

The Baymard Institute found that “92% of top ecommerce sites have inadequate form field descriptions in their checkout process”, driving up errors. That’s just in ecommerce - the number is likely to be similar for all forms.

You should review your form, asking:

This won’t reduce your error rate to zero, but it will help.

Using Zuko to track error messages

Zuko’s Custom Event tracking allows you to push the occurrence of error messages into Zuko as custom events.

This will give you an overview of which error messages are being shown most often, which occur most frequently in both abandoned and completed sessions, and also show you how many times on average they occured:



Here, you’ll want to keep an eye out for both error messages that occur for a wide percentage of people (is the field label unclear?) and also for errors that occur multiple times (is the validation broken for this field?).

This powerful feature gives you the ability to pinpoint quickly what mistakes your users are making and improve your UX by helping users correct their errors quickly and easily.

Some further reading:

Ux Design - Four Ways to Display Error Messages - Nomensa

Adaptive Validation Error Messages - Baymard

Error Messages - ConversionXL

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