See how your page will look in Google before you publish. This measures your title and description by pixel width, the way Google actually truncates them, not just by character count.
Check your whole page Generate schema
Google cuts off titles and descriptions at a pixel width, not a fixed number of characters. A wide letter like W or M takes far more room than a narrow one like i or l, so two titles with the same character count can truncate completely differently. Counting characters gives you a rough guide. Measuring pixels, as this tool does, tells you what will actually show.
As a rule of thumb, keep titles within about 600 pixels on desktop (roughly 50 to 60 characters) and descriptions within about 920 to 990 pixels (roughly 150 to 160 characters). Mobile shows a little more. Whatever the limit, front-load the important words, so your message still lands even if the end is trimmed.