<b>The third of a second that cost six figures</b>

<b>The third of a second that cost six figures</b>

A travel-deals affiliate had a page that loaded in 1.4 seconds — respectably fast. Revenue per session, though, was oddly weak on mobile.

The clue came from banding sessions by load time. Sessions that loaded under 2.5 seconds converted normally. A hidden 18% of mobile sessions, mostly on older Android, were quietly loading in 5–8 seconds because a third-party offer script blocked render. The 1.4s average buried them completely.

They deferred the offer script and inlined the critical content.

For that slow band, conversion rose from 0.4% to 1.6%, and overall mobile revenue per 1,000 sessions went from $42 to $58. The 'average' page was always fine. The tail was bleeding.

The lesson: an average load time hides the slow sessions that hurt most. Band your speed data and look at who's actually waiting.