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Mohd Baquir Qureshi

Technical Blog
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E-commerce

The Impact of Site Speed on E-commerce Conversion Rates

By Mohd Baquir Qureshi •
Speed metrics

In 2006, Amazon found that every 100ms of latency cost them 1% in sales. Today, on mobile networks, the penalty is even steeper. A site that loads in 2 seconds has an average conversion rate of 2.05%. A site that loads in 4 seconds drops to 1.15%.

Core Web Vitals

Google has made page speed a ranking factor through Core Web Vitals. If you fail these, you not only lose the customer who clicked your ad, but you lose the organic rank that got them there in the first place.

  • Largest Contentful Paint (LCP): Must be under 2.5 seconds. Optimize this by preloading your main product image.
  • Cumulative Layout Shift (CLS): Keep under 0.1. Fix this by specifying width and height attributes on all images so the browser reserves space before the image loads.
  • Interaction to Next Paint (INP): Replaced FID. Ensure your JavaScript execution doesn't block the main thread when a user clicks "Add to Cart."

The Third-Party App Problem

In the Shopify ecosystem, site speed degradation is almost entirely caused by installing too many apps. Heatmaps, live chat widgets, and review integrations load heavy scripts. Consolidate your apps, remove unused ones entirely, and defer loading non-critical scripts until the user scrolls.