Where the numbers come from
Bounce risk uses Google's 2017 mobile benchmark study with SOASTA. As page load time goes from 1 to 3 seconds, the chance of a bounce rises 32%. From 1 to 5 seconds it rises 90%, from 1 to 6 seconds 106%, and from 1 to 10 seconds 123%. The tool draws a line between those points.
Conversions use Deloitte's 2020 study Milliseconds Make Millions, which found that a 0.1 second faster mobile site lifted retail conversions by 8.4% on average. To stay conservative, the tool counts at most 10 of those steps and adds them, not compounds them.
What usually makes a local business site slow
- Uncompressed hero photos straight from a phone or stock site, often 3 to 6 MB each.
- Page builders loading every widget's scripts on every page.
- Chat widgets, review sliders and tracking pixels that block the first paint.
- Cheap shared hosting with slow server response.
Test any page in Google's PageSpeed Insights and look at the Core Web Vitals section: Largest Contentful Paint under 2.5 seconds, Interaction to Next Paint under 200 ms, and Cumulative Layout Shift under 0.1.
Sources: Think with Google, "Find out how you stack up to new industry benchmarks for mobile page speed" (2017). Deloitte Digital, "Milliseconds Make Millions" (2020).