Online purchases surged 14.5%.
Sales on ecommerce web sites reached $80bn in Q1, increasing 3.5% from the corresponding quarter in 2014, as icy weather kept shoppers at home but not from shopping.
According to seasonally-adjusted figures released by the US Department of Commerce, total retail sales dropped 1.5%, the first quarterly decline in three years.
Meanwhile, online purchases surged 14.5% on a year-over-year basis, compared with a 1.6% rise for total sales.
After the declines in 2008 and 2009, ecommerce sales have recovered and averaged 3.7%. The number was 1.1% for total sales.
The share of ecommerce as a percent of total retail sales increased to 7% from 0.6% in 1999.
Bloomberg Intelligence analyst Poonam Goyal said within certain categories, like apparel, the shift to the Internet has been faster.
"Companies that generate the largest portion of their sales from online are apparel stores. Their online sales are often more than 15 percent of their total sales, so the potential there is enormous."