From retail to ecommerce, the outlook for Holiday 2015 is bright.

By Rieva Lesonsky

More than holiday bells will be ringing this December. According to a forecast from eMarketer, holiday retail sales will have cash registers ringing this fall (yes, I know most don’t actually “ring” anymore).

The company says U.S. retail sales in November and December will hit $885.70 billion, a 5.7 percent year-over-year increase. This is the largest increase since 2011, and substantially higher than the 3.2 percent growth rate that was originally forecast earlier this year.

Partly driving the heavy spending, eMarketer says, is the dramatic drop in gas prices over the past year. eMarketer analyst Monica Peart also credits “increases in real income from wages, further decreases in unemployment and an increased willingness to spend in traditional retail categories.”

Online retailers will see their share of the action as well. eMarketer says online sales will “play an increasingly important role this season,” and estimates ecommerce holiday sales will hit $79.4 billion, which is 9 percent of total retail sales, up from its 8.3  percent share last year.

And let’s not forget mobile sales. Mcommerce sales, predicts eMarketer, will jump 32.2 percent for 2015, more than double the 14.2 percent increase forecast for ecommerce sales in general. The biggest growth, says the research company, will come in sales via smartphones. And they estimate that by the end of 2016, 25 percent of retail ecommerce sales in America will take place via mobile devices.