SERP snippet preview
How your result will look, with truncation measured the way Google does it. Switch between desktop and mobile widths.
example.com
Your title appears here
Your meta description appears here, truncated the way Google truncates it.
Rendered on white regardless of your theme, because that is where it will be read.
Why does my snippet look different in real results?
Google rewrites titles and descriptions when it thinks something else on the page fits the query better, and it bolds words matching the query. A preview shows what you supplied, which is the part you control.
Does mobile truncate differently?
Yes, and usually sooner, because the column is narrower. Most traffic is mobile, so check that width before the desktop one.
Other tools
This tool checks one page at a time. Visorank does the same work across every page on your site continuously, and shows you which queries people actually search rather than estimates.
What Visorank does