The Trainline reduced latency by 0.3 seconds across their funnel and customers spent an extra £8 million (~$11.5 million) a year. Permalink Share on Twitter

Financial Times added a one second delay to every page view and saw a 4.9% drop in the number of articles users read over a 7 day window. A two-second delay resulted in a 4.4% drop, and a three second delay saw a 7.2% drop. After twenty-eight days the two and three second variants both resulted in further drops in engagement. Permalink Share on Twitter

Instagram increased impressions and user profile scroll interactions by decreasing the response size of the JSON needed for displaying comments (by 33% for the median and 50% for the 95th percentile for the main endpoint). Permalink Share on Twitter

TRAC Research found, in a survey of 300 companies, that the average revenue loss for an hour of downtime was $21,000. For the same set of companies, average revenue loss due to an hour of slow performance (defined as load times exceeding 4.4 seconds) was $4,100. Website slowdowns occurred ten times more often than outages. Permalink Share on Twitter

Staples reduced median homepage load time by 1 second and reduced load time for the 98th percentile by 6 seconds. As a result, they saw a 10% increase in their conversion rate. Permalink Share on Twitter

GQ cut load time by 80% and saw an 80% increase in traffic. Median time spent on the site also increased by 32%. Permalink Share on Twitter

AutoAnything reduced page load time by 50% and saw an 12-13% increase in sales. Permalink Share on Twitter

Glasses Direct found that for every second they added to the load time, there was a 6.7% decrease in conversions. In addition, load time for users who did not convert was 3-4 times as high as for converting customers. Permalink Share on Twitter

Etam reduces it's average page load time from 1.2s to 500ms and increased conversions by 20%, time on site by 21%, and pages viewed per visit by 28%. Permalink Share on Twitter

When YouTube introduced a version of their pages that was 90% lighter, they saw a large increase in traffic in areas with poor connectivity such as Southeast Asia, South America, Africa and Siberia. Permalink Share on Twitter