Layout shift direction (lateral vs downward) and Cumulative Layout Shift
Horizontal lateral shifts (81.2%) versus downward vertical shifts (54.1%): how shift direction across 134,799 sites predicts real-user Cumulative Layout Shift.
81.2% of sites use lateral horizontal layout shift direction, and 86% of those sites have a good CLS, against 89% of all sites.
CLS pass rate
Sites with lateral horizontal layout shift direction have a good CLS most often: 86%, against 89% of all sites. Sites with downward vertical shift direction have it least often, at 84%.
Layout shift direction usage
Lateral horizontal is the most used: 81.2% of sites.
Understanding layout shift direction
Why downward vertical shifts carry a larger distance fraction
Cumulative Layout Shift multiplies impact fraction by distance fraction. Horizontal shifts (81.2% of shifting sites, 86% good field CLS) typically nudge navigation items by a few pixels during font swap, whereas downward shifts (54.1% of shifting sites, 84% good field CLS) push the entire main column down when top banners or unsized heroes expand.
Audit downward vertical shifts (54.1% of shifting sites, 84% good CLS) by checking for late-injected announcement bars, cookie banners inserted into document flow, and unsized hero containers. Render overlays with position: fixed rather than pushing document content down, and reserve fixed heights for top-of-page slots.
How layout shift direction plays out per platform
What the field data shows when you isolate a single CMS or framework.
WordPress 46,419 sites WordPress sites with downward layout shifts (49.7%) pass field CLS at 86% vs 88% for lateral shifts.
Across 46,419 shifting WordPress sites, 83.2% record horizontal shifts (88% good field CLS) and 49.7% record downward vertical shifts (86% good CLS).
Shopify 5,582 stores 50.2% of shifting Shopify stores record downward shifts (90% good CLS).
Across 5,582 Shopify stores with recorded lab shifts, 83.5% record horizontal shifts (91% good field CLS) and 50.2% record downward vertical shifts (90% good CLS).
Wix 1,198 sites Shifting Wix sites pass field CLS at 96% on lateral shifts and 95% on downward shifts.
Across the 1,198 Wix sites with a lab layout shift, 72.0% record lateral movements (96% good field CLS) and 45.7% record downward shifts (95% good CLS).
By Arjen Karel · 210,902 crawled sites (126,761 with phone Chrome field data, 134,799 sites with layout shift direction, October 2026). How we measured.