Although there is no specific number of characters required in a title tag, Google usually displays the first 50 to 60 characters when delivering search results based on the screen size you are using. If the title tag is longer than 60 characters, important elements of the title might be lost, such as the keywords or a call to action.
Traditionally, title length was measured in character length; today, search engines measure the length of a title tag in pixels, the smallest building block of your screen. The minimum suggested length of a title tag is 285 pixels; this would equal rough 30 characters. In terms of the maximum length, 575 pixels would be the max, which equates to 60 characters in length.