In Search Engine Optimization the ideal length of Meta Title should be 54 - 60 characters and for Meta Description should be 140 - 160 characters maximum.
The meta description should employ the keywords intelligently, but also create a compelling description that a searcher will want to click. Direct relevance to the page and uniqueness between each page’s meta description is key. The description should optimally be between 150-160 characters.
Google typically displays the first 50-60 characters of a title tag
Title and description tags are limited to 600 pixels in Google which is usually up to 60 characters but it can be a few less, depending on the letters used. It was 512 but was recently increased to 600.
Google actually goes by pixels instead of characters since some letters (like "W" for example) are wider than others.