- Conversion rates down 55% among online shoppers Online conversions rates among UK shoppers are down almost 55% in the past five years, according to the latest IMRG Capgemini e-Retail Sales Index. In 2006 the average online conversion rate was 8.4%, but this figure has steadily declined to 3.8% in 2011 as consumers shift from 'online purchasing' to 'online shopping'.