What's the importance of page loading speed for conversion rates?

Page Loading Speed and Conversion Rates

Page speed is one of the few conversion factors with unambiguous, quantified research supporting its impact. Amazon found each 100ms improvement increased revenue by 1%; Google found a 1-second delay reduces conversions by 7%. Portent's research showed pages loading in 1 second convert at nearly 3x the rate of pages loading in 5 seconds. For mobile e-commerce with high social traffic - where impulse buyers expect instant gratification - this relationship is even more pronounced.

Speed Impact on Conversion by Load Time

Core Web Vitals to Monitor

• LCP (Largest Contentful Paint): Time for the largest visible element (hero image) to load. Target: under 2.5 seconds
• INP (Interaction to Next Paint): Time from user tap to visual response. Target: under 200ms
• CLS (Cumulative Layout Shift): Amount of unexpected layout movement as page loads. Target: under 0.1

Highest-Impact Speed Improvements for Shopify

• Convert images to WebP format (25-35% size reduction at same quality)
• Remove unused Shopify apps - each app typically adds 50-200ms of JavaScript load time
• Lazy load all below-fold images with loading="lazy"
• Use Google PageSpeed Insights (mobile tab) to identify specific improvement opportunities with estimated impact scores
• Consider switching to Dawn or a performance-optimized Shopify theme if current theme scores below 60 on mobile PageSpeed