Render-blocking scripts
47.7%
of the 3,044 free scans considered in the last 30 days raised this finding. That is 1,451 scans across 1,445 distinct sites. 95% interval 45.1% to 50.2%.
What it means
External scripts loaded without defer or async stop the browser from drawing the page until each one has downloaded and run. Every one of them is a pause before the first thing a visitor sees.
How to fix it
Add defer to any script the first paint does not need, and load marketing and chat tags last. A script the page cannot draw without belongs inline or first, and there is rarely more than one.
How to check it yourself
View source and look at the script tags in the head. Any without a defer or async attribute will block the page from drawing until it loads.
What fixed looks like
Scripts in the head carry defer or async, so the browser draws the page without waiting on them.
How we measured this
Go Voltic scans a site and records which findings it raises. The share above is over every free four-page scan in the last 30 days that loaded at least one page, which is 3,044 scans. Deep scans of paid reports and of the research sweep read a site at a different depth and are a separate population, never in this denominator. It is not a survey and it is not an estimate: it is a count of what our own scanner found. Sites are counted once each in the distinct-sites figure, so a site scanned twice does not weigh double there.
The interval is a 95% Wilson interval. A share printed without its sample size reads as certainty and is indistinguishable from a guess, so both are always shown. Figures on this page were computed on 2026-09-08.
The same share sits beside every other finding on the benchmarks page, which also carries the whole table as CSV and JSON and says how to cite it.
Check your own site
The free scan reads four pages and reports every finding it raises, including this one. It takes about ten seconds and asks for nothing but the address.