How to read the result
The bar fills as you type and the dashed line marks the halfway point. A title between roughly 30 and 60 characters says enough about the page and usually fits. Shorter than that and it tells a searcher very little. Longer and Google is likely to cut it, sometimes on the word that mattered most. See title tag in the glossary for the short version.
A meta description between roughly 70 and 160 characters has room for what the page gives, who it is for and one reason to click. It is not a ranking factor, and Google often shows its own text instead, so put the most important part first. The meta description entry explains why.
These are guidelines, not rules. Google measures width in pixels, so a title full of wide letters is cut sooner than one full of narrow ones. To check what is actually on a published page, including the title Google can see, use the free audit.
A title that fits is not yet a good title
Length is the easy part. A title also has to say what the page is, in the words a person would search for, and give one reason to choose it over the result above. Lead with the topic, add the angle, and put your brand last, where it is the first thing to drop if space runs out. The first On-Page SEO lesson has before-and-after rewrites for a blog post, a product page and a service page.