The Ideal Search Box Is 27-Characters Wide
What’s the ideal width of a search box? Is there such a thing? It turns out that most of today’s search boxes are too short. The problem with short boxes is that even though you can type out a long query, only a portion of the text will be visible at a time, making it difficult to review or edit what you’ve typed.
Research has found that the average search box is 18-characters wide. Quite often queries are too long to fit into the search field. Extending the box to 27 characters will accommodate 90% of queries. Remember, you can set widths using ems, not just pixels and points. One em is the width and height of one “m” character (using whatever font size a website is set to). So, use this measure to scale the width of the text input field to 27-characters wide.
Google’s search box is wide enough to accommodate long sentences.
Apple’s search box is a little too short, cutting off the query, “Microsoft Office 2008.”
In general, search boxes are better too wide than too short, so that users can quickly review, verify and submit the query. This guideline is very simple but unfortunately too often dismissed or ignored. Some padding in the input field can also improve the design and user experience.