The before-after test that put a dollar value on page speed

The before-after test that put a dollar value on page speed

A travel booking site knew their search results page was slow but couldn't justify the engineering cost. "Faster is better" doesn't win budget meetings. They needed a number.

The speed-to-revenue playbook:
— In GA4, build conversion rate segmented by page load time buckets
— Group sessions into under-2s, 2-4s, and over-4s on the key page
— Compare conversion rate across the three buckets
— Estimate revenue at risk by applying the fast-bucket rate to slow sessions
— Ship the optimization to one cohort and measure the real lift

The under-2s bucket converted at 4.4%, the over-4s at 1.7%. Roughly 30% of sessions sat in the slow bucket. After a caching fix dropped median load to 1.9s, that cohort's conversion rose to 3.8%, worth an estimated $40k a month.

Lesson: "faster is better" loses budget fights. A conversion-by-speed bucket wins them.