BBC has seen that they lose an additional 10% of users for every additional second it takes for their site to load Permalink Share on Twitter

Ancestory.com saw a 7% increase in conversions after improving render time by 68%, page weight by 46% and load time by 64%. Permalink Share on Twitter

AliExpress reduced load time by 36% and saw a 10.5% increase in orders and a 27% increase in conversion for new customers. Permalink Share on Twitter

According to Google's DoubleClick, when comparing sites that load in 5 seconds to sites that load in 19 seconds, the faster sites had 70% longer average session lengths, 35% lower bounce rates and 25% higher ad viewability than their slower counterparts. Permalink Share on Twitter

Google's DoubleClick found that publishers whose mobile sites load in 5 seconds earn up to 2x more mobile ad revenue than sites loading in 19 seconds. Permalink Share on Twitter

For every 100ms decrease in homepage load speed, Mobify's customer base saw a 1.11% lift in session based conversion, amounting to an average annual revenue increase of $376,789. Similarly, for every 100ms decrease in checkout page load speed, Mobify's customers saw a 1.55% life in session based conversion, amounting to an average annual revenue increase of $526,147 Permalink Share on Twitter

Optimizely added artificial latency to the Telegraph and saw page views plummet: by 11% for a 4 second delay and 44% for a 20 second delay. Permalink Share on Twitter

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