What a real website speed audit actually finds

Before we rebuild any client's site, we run a full Lighthouse audit and write down the actual numbers. Over the last year we did this for 12 client sites before touching a single line of code. The results were consistent enough that they're worth sharing, because the causes were rarely what clients expected going in.

The starting scores were worse than "a bit slow"

The average incoming Lighthouse performance score across those 12 sites was 41 out of 100 on mobile. Only two sites scored above 60. Most owners described their site as "a little slow to load" — the actual gap between that impression and the measured reality was the first surprise for nearly every client we showed this to.

Three causes accounted for almost everything

We expected a long tail of small issues. Instead, three problems showed up on 10 of the 12 sites:

• Unoptimized images. Nine sites were serving full-resolution camera photos (often 4,000px wide) resized down with CSS instead of at the actual file level. One homepage hero alone was a 6.2MB JPEG displayed at 1,200px wide.
• A page builder loading four separate CSS frameworks. Seven sites had accumulated plugin-driven page builders that each shipped their own grid system, icon font, and animation library — most of which were never fully removed when the site's design changed.
• Render-blocking third-party scripts. Six sites loaded a chat widget, two different analytics tools, and a marketing pixel all synchronously in the document head, each one blocking the page from painting until it finished loading.

What changed after our rebuild process

Once we moved a site through our standard build (hand-coded HTML/CSS, responsive image sets generated at actual render sizes, deferred or removed third-party scripts), the average mobile performance score across those same 12 sites rose to 96. Every site launched with all four Lighthouse categories — Performance, Accessibility, Best Practices, and SEO — at 95 or above.

The business impact varied by site, but the two we tracked closest were revealing: Northgate Outfitters' cart abandonment rate dropped from 71% to 44% in the first month after their rebuild launched, and a separate client's organic search sessions rose 18% over the following quarter with no new content published — just faster load times feeding into Google's ranking signals.

"The slowest single element on any site we audited was a 40-second product video, autoplaying, muted, at full resolution — on a mobile connection."

From our internal audit review, June 2026

The one-question test we now run first

If you want a rough read on your own site before commissioning a full audit, open your homepage on a phone using mobile data (not wifi) and time how long it takes until you can actually tap something. Anything past 4 seconds is costing you real visitors — Google's own research puts bounce probability at 90% by the 5-second mark on mobile.

If that number is uncomfortable, our web design and build service starts with the same audit we ran here, and we'll show you your actual numbers before you commit to anything.