Forms: Use visible input hint next to field or hidden hint behind info icon?

Question

In case a label doesn't provide sufficient information for an input field and an additional hint is helpful, when should the hint be available next to (or below) the input field and when should it be hidden behind an info icon?

Four criteria I thought off: - In case the hint exceeds 100 words, use the information icon - In case the hint includes a link to further information, use the information icon - In case the hint relates to an infrequent action and is not intuitive (e.g. Maximum upload size), show text directly - In case the hint is only relevant for novice users, use the information icon

Are these correct and what criteria are missing?

Thanks in advance!

Answer 1

Don't use tooltips to give useful information about how to fill in the form. Tooltips should really be reserved for explaining what a field is (i.e. 'what does this word mean').

A good set of design guidelines for forms is the GOV.UK GDS, as this has been usability tested and is about as accessible as a set of design standards can be.

Their recommendation is

Hint text

• don’t use placeholder text in form fields, as this will disappear once content is entered into the form field
• use hint text for supporting contextual help, this will always be shown
• hint text should sit above a form field
• ensure hint text can be read correctly by screen readers