Web Development Apr 22, 2026 5 min read
Why a 1-Second Speed Boost Lifted Conversions 12%
A case study from a recent e-commerce build that paid for itself in 3 weeks.
Rank Enhancers Editorial
Digital Marketing Team
Speed isn't a vanity metric. It's revenue. Here's how a 1.1-second reduction in LCP on a recent Shopify build translated to a 12% lift in conversion rate.
Where the seconds went
We migrated from a heavy theme to a custom headless setup, swapped a slow image CDN, deferred non-critical JS, and preloaded the hero font and image.
Numbers that mattered
LCP from 3.4s to 2.3s. CLS from 0.18 to 0.02. Mobile add-to-cart rate +18%. Checkout completion rate +9%. Conversion rate +12%.
Pays for itself
Build budget was recouped in 3 weeks of added revenue. Speed is the highest-leverage CRO project most stores never run.
Web Development