Vodafone: A Faster Page Lifted Sales 8%

When a board reviews "site speed" it usually lands in the IT column, filed next to server costs and uptime. That framing is wrong. Page performance is a revenue lever, and the cleanest proof is a controlled experiment Vodafone ran on a landing page where the only variable that changed was how fast the page loaded. No new offer, no redesign, no extra ad spend. The result reframes Core Web Vitals from a technical chore into a measurable line on the P&L.

The situation

Vodafone, one of the world's largest telecommunications companies, wanted to know whether investing engineering time into Core Web Vitals would actually move business numbers, or whether it was purely a hygiene exercise. Rather than guess, they designed a clean A/B test on a landing page fed by paid media across display, iOS and Android, search, and social channels. Half the traffic went to an optimized version of the page, half to the existing baseline. Each version received roughly 100,000 clicks and 34,000 visits per day, a sample large enough to trust the outcome.

What was done

The discipline of the test is what makes it credible to a skeptic. Version A and Version B had no functional or visual differences. The page looked identical to the user. The single change was that Version A was tuned for Web Vitals: the rendering logic for a widget was moved from the client side to the server side, which cut the amount of render-blocking JavaScript the browser had to process before showing meaningful content. That one architectural decision improved Largest Contentful Paint, the metric that measures how quickly the main content of a page becomes visible, by 31%.

The result

The faster page did not just score better in a lab tool. It sold more. According to Vodafone's reported results, the 31% improvement in LCP produced an 8% increase in sales, a 15% improvement in the lead to visit rate, and an 11% improvement in the cart to visit rate. Because the experiment isolated speed as the only variable, those gains can be attributed to performance rather than to seasonality, creative, or budget changes. The absolute figures were redacted, but the percentages are the meaningful part: the same traffic, the same spend, converting materially better because the page got out of the user's way faster.

Why it matters for you

If your organization is buying paid traffic, you are already paying for every visit. A measurable share of those visitors abandon before the page finishes loading, and that loss is invisible in most dashboards. The Vodafone test puts a number on the upside of fixing it: an 8% lift in sales from a single rendering change. Run the math against your own paid acquisition budget and the question stops being "can we afford to optimize performance" and becomes "what is it costing us not to." Core Web Vitals are not an IT preference. They are a conversion input, and they are one of the few you can improve without spending more to acquire the click.

Source: web.dev: Vodafone: A 31% improvement in LCP increased sales by 8%