--- title: "We Measured Every Analytics Script. Here Is What We Found." description: "We downloaded major analytics scripts from production CDNs and measured their real size. GA4 is 132x heavier than SealMetrics, which came out the lightest of the ten." canonical_url: "https://sealmetrics.com/blog/we-measured-every-analytics-script/" lang: "en" date_modified: 2026-05-04 content_type: "blog" owner: "content" llm_priority: "useful" last_verified: "2026-05-04" source: https://sealmetrics.com/blog/we-measured-every-analytics-script/ publisher: SealMetrics --- Performance # We Measured Every Analytics Script. Here Is What We Found. February 20, 2026 4 min read By [Rafa Jiménez](https://sealmetrics.com/authors/rafa-jimenez/) ## Key Takeaways - GA4 is 132x heavier than SealMetrics (145.6 KB vs 1.1 KB gzipped), and the Adobe stack is 155x heavier at ~170 KB. SealMetrics was the lightest measured, ahead of Plausible at 1.3 KB. - For a site with 100,000 monthly visitors, GA4 consumes 14.9 GB of bandwidth per month versus 113 MB for SealMetrics. - Enterprise analytics scripts carry legacy code for cross-site tracking and fingerprinting — features now illegal under GDPR or blocked by browsers. - At 1 million pageviews/month, GA4 generates approximately 30 kg of CO2 annually versus 0.6 kg for SealMetrics. We downloaded the main analytics scripts from every major provider — directly from their production CDNs. Not from documentation pages. Not from marketing claims. The actual minified, gzipped files that load on your visitors' browsers. **Method.** One GET per script with `Accept-Encoding: gzip`, bytes counted on disk, response headers read from the same request. “On the wire” is what actually crosses the network; “uncompressed” is what the browser then has to parse. Measured 9 August 2026 — vendors ship changes constantly, so treat these as a dated snapshot rather than fixed constants. **† Adobe is measured differently.** Adobe Analytics has no single public script to fetch: it loads as a per-customer Launch container plus AppMeasurement, the ActivityMap module and rule payloads. Those figures come from a field measurement on a real European media site running Adobe and SealMetrics side by side — ~150 KB for the Launch container and ~20 KB for AppMeasurement and modules, ~170 KB in total. It is a real number from a real page, but it is a stack, not a single file, so it is not strictly like-for-like with the rows above. ## The raw numbers | Tool | On the wire (gzip) | Uncompressed | | --- | --- | --- | | SealMetrics | 1.1 KB | 1.9 KB | | Plausible | 1.3 KB | 2.8 KB | | Fathom | 2.0 KB | 6.7 KB | | Simple Analytics | 3.8 KB | 7.3 KB | | Piwik PRO | 26.2 KB | 67.5 KB | | Mixpanel | 32.6 KB | 101.5 KB | | Matomo | 46.2 KB | 152.5 KB | | PostHog | 76.2 KB | 237.8 KB | | Google Analytics 4 | 145.6 KB | 409.4 KB | | Adobe Analytics † | ~170 KB | ~730 KB | SealMetrics 1.1 KB Plausible 1.3 KB Fathom 2.0 KB Simple Analytics 3.8 KB Piwik PRO 26.2 KB Mixpanel 32.6 KB Matomo 46.2 KB PostHog 76.2 KB Google Analytics 4 145.6 KB Adobe Analytics ~170 KB GA4 is 132x heavier than SealMetrics, and the Adobe stack is 155x heavier. SealMetrics is the lightest of the ten, just ahead of Plausible. GA4 is 52x heavier than the 2.5 KB SealMetrics script in this test. Weigh your own stack on your own pages and compare. [Book a demo](https://sealmetrics.com/demo/)[See pricing](https://sealmetrics.com/pricing/) ## What these numbers actually mean For a site with 100,000 monthly visitors, [GA4's script](https://developers.google.com/tag-platform/gtagjs) alone consumes 14.9 GB of bandwidth per month. SealMetrics consumes 113 MB. That is not a rounding error — it is a 132x difference in network resources, battery drain, and page load time. 53% of mobile users abandon sites that take more than 3 seconds to load. Heavy analytics scripts contribute directly to that latency through Total Blocking Time, [Interaction to Next Paint](https://web.dev/articles/vitals)delays, and bandwidth competition with your actual content. ## Why are enterprise scripts so heavy? Enterprise analytics tools carry legacy code for features that are now either illegal under GDPR or blocked by browsers. Cross-site tracking, third-party cookie management, fingerprinting modules — your visitors pay the performance cost for features you can not legally use. ## The environmental cost At 1 million pageviews per month, GA4's script generates approximately 30 kg of CO₂ annually — equivalent to driving 120 km. SealMetrics' equivalent: 0.6 kg, or about 2.4 km. Data transfer consumes energy. The lighter the script, the lower the environmental footprint. At scale, the difference is significant. ## How we measured We downloaded scripts directly from production CDNs — the same files that load on real visitor browsers. We measured minified file sizes and applied standard gzip compression for consistency across all tools. No marketing claims, no documentation numbers. Just the actual bytes. ## The bottom line The script that measures your site performance is itself degrading your site performance. A 1.1 KB script captures 100% of traffic through [cookieless first-party collection](https://sealmetrics.com/how-it-works/), complies with [GDPR by design](https://sealmetrics.com/glossary/gdpr-analytics-compliance/), and loads in under 50ms. The question is not whether you can afford to switch — it is whether you can afford not to. [Calculate how much data you are losing](https://sealmetrics.com/data-loss-calculator/). Script weight is a tax every visitor pays on every pageview. See what measurement at 2.5 KB changes in your Core Web Vitals. [Book a demo](https://sealmetrics.com/demo/)[See pricing](https://sealmetrics.com/pricing/) ### Related articles [The Hidden Conversion Killer: How Analytics Scripts Are Costing You Sales](https://sealmetrics.com/blog/analytics-scripts-costing-you-sales/)[Cookieless Analytics Explained: How to Measure Without Cookies](https://sealmetrics.com/blog/cookieless-analytics-explained/) ## Related reading [The Hidden Conversion Killer: How Analytics Scripts Are Costing You Sales](https://sealmetrics.com/blog/analytics-scripts-costing-you-sales/) 3 min read [Your Analytics Tool Contacts 7 Domains. Here Is Why That Matters.](https://sealmetrics.com/blog/analytics-tools-external-domains/) 4 min read [Every Cookie Set by Every Major Analytics Tool, Cataloged](https://sealmetrics.com/blog/analytics-tools-cookies-cataloged/) 5 min read