ZenovayTools

Analytics Speed Tax

Calculate the total performance cost of your analytics and marketing scripts. See projected LCP/FCP scores without them.

How to Use Analytics Speed Tax

  1. 1Enter your website URL.
  2. 2The tool detects all analytics and marketing scripts.
  3. 3Review the total KB, blocking time, and LCP/FCP impact.
  4. 4See projected page speed scores without the analytics tax.
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Frequently Asked Questions

How does the Analytics Speed Tax work?▾
We fetch your page HTML and detect analytics, advertising, session replay, chat, and CRM scripts. Each script has a known performance profile based on transfer size, main-thread blocking time, and LCP impact. We calculate the combined overhead and project what your Core Web Vitals would look like without them.
Are the performance numbers exact?▾
No. These are estimates based on typical script profiles and real-world performance data. Actual impact varies based on network conditions, device capability, and how scripts are loaded. The numbers give you a relative comparison, not absolute measurements.
What is LCP?▾
Largest Contentful Paint (LCP) measures how long it takes for the largest visible element to render. Google recommends LCP under 2.5 seconds for a "Good" rating. Analytics scripts can delay LCP by competing for network bandwidth and main-thread execution time.
What does "render blocking" mean?▾
A render-blocking script prevents the browser from painting content until it has downloaded and executed. Scripts in the <head> without async or defer attributes are render-blocking. A/B testing tools are often intentionally render-blocking to prevent content flicker.
Does removing scripts actually improve speed?▾
Yes, but the improvement depends on which scripts you remove. Chat widgets and session replay tools typically have the largest impact due to their size. Privacy-friendly analytics like Plausible or Fathom add minimal overhead (1-2 KB).
What is consent overhead?▾
If your site uses cookie-based trackers, you need a Consent Management Platform (CMP). The CMP itself adds 30-80 KB of JavaScript and must load before other scripts. Switching to cookieless analytics eliminates this extra overhead entirely.