Google typically displays the first 50–60 characters of a title tag. If you keep your titles under 60 characters, our research suggests that you can expect about 90% of your titles to display properly.
Meta descriptions can be any length, but Google generally truncates snippets ~300 characters (this limit increased in December 2017). It's best to keep meta descriptions long enough that they're sufficiently descriptive, so we recommend descriptions between 50–300 characters.