We Measured Every Analytics Script. Here Is What We Found.

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

GA4 is 132x heavier than SealMetrics, and the Adobe stack is 155x heavier. SealMetrics is the lightest of the ten, just ahead of Plausible.

What these numbers actually mean

For a site with 100,000 monthly visitors, GA4's script 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 Paintdelays, 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, complies with GDPR by design, 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.