About the Google SERP Preview Tool
Your title tag and meta description are your ad in Google. Google truncates titles at about 600 pixels on desktop (not a fixed number of characters — 'W' is far wider than 'i'), and descriptions at about 920 pixels on desktop and fewer on mobile.
Nuqti measures your text in pixels using the same font Google uses, shows where the '…' will appear on desktop and mobile, and renders the full result card so you can polish it before publishing.