I'm working with a site that is currently making heavy use of comboboxes. In fact, every select in the whole application is automatically turned into a combobox on page load.

My first inclination is to take everything back to being a select and start comboboxing them on an as-needed basis.

But the question has arisen, when is a combobox really more appropriate than a select field?

(Combobox: a select-like dropdown of possible values, with a complimentary auto-complete style typing field at the top, which filters down the list as you type)

  • 1
    What is your definition of a combobox? Surely a combobox is only appropriate if the user should be able to enter a free text value?
    – Matt Obee
    Jan 18, 2013 at 16:06
  • 1
    @MattObee: Comboboxes are frequently used in "only from this list" scenario's where typing in the edit part of the combo is only allowed (if at all) to facilitate selecting the desired value. In general they are used when the list is too long for a simple listbox and values need to be selected from a more-or-less fixed set, or the values come from a table maintained in another part of the application. Jan 18, 2013 at 16:19
  • I think this is worth a read ux.stackexchange.com/questions/31738/…. It will depend on how scannable your values in the select boxes are.
    – icc97
    Jan 18, 2013 at 16:26
  • thanks @MattObee for that, your description is better than mine, but for the sake of clarity I wrote a short description of it in the question.
    – Kristian
    Jan 18, 2013 at 16:30

2 Answers 2


A combobox is a good choice when you have information that needs to be free form. Such as a name, phone number, or email address.

Use a select box when you want someone to choose between a few distinct options. Such as: male or female; yes or no; red, blue, or black.

  • 1
    If its that few i.e. three or less it should just be radio buttons
    – icc97
    Jan 18, 2013 at 16:24
  • @JohnGB the choices definitely are distinct and require a selection from the finite list of options, however, at times, there are more than a hundred options in the select field. Your thoughts?
    – Kristian
    Jan 18, 2013 at 16:27
  • @icc97 poor examples from me. There are many cases when you want to choose one or more, and that is what I was referring to.
    – JohnGB
    Jan 18, 2013 at 16:38

You could make any list with more than N items a combo-box and any with N items or less a select. Exactly what the cutoff N is could be determined by testing - it should be easy to plug in different values and see which threshold feels best. My guess is that a good threshold would be around 15 items.

If you do this and are able to test with realistic users, one thing I'd watch for is to see if anyone is surprised or disappointed that one of the selects didn't work like a combo-box, that is they became acclimated to the combo-boxes and came to expect that behavior throughout. Maybe leaving them all combo-boxes is the better design.

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