Why pixels, not characters
Google cuts a title when it runs out of room on the screen, so a title full of W and M is cut sooner than one full of i and l. Character limits you see quoted (60 for titles, 155 for descriptions) are rough translations of a width.
This tool measures the text in 20 px Arial for titles and 14 px Arial for descriptions and compares it with the widths commonly observed on desktop results: about 600 px and about 920 px. Google doesn't publish these numbers and changes its layout, so treat the meter as a guide.
Google may show something else
Google's documentation says title links are generated automatically from several sources, including the title element, headings and anchor text, and that the snippet usually comes from the page content, with the meta description used when it describes the page better. A preview shows what you control, not a guarantee.
Writing titles that survive the cut
- Put the words that answer the search first; the site name can go last or be dropped
- One topic per title. Repeating the keyword three times reads as spam and Google may rewrite it
- Avoid ALL CAPS and long lists of separators
- Give every page its own title and description; duplicates are often replaced
- Write the description as a short, specific summary of the page, not a list of keywords