Final shipping dates to get gifts via ground delivery in time for Christmas

With a shortened shopping window before Christmas, retailers are feeling the pressure to deliver on speedy shipping.

The shipping industry has six fewer days than normal between Thanksgiving and Christmas to get what could be more than 2 million packages delivered on time.

E-commerce sales are expected to reach $155 billion this holiday season which will add to the challenge of fulfilling shipments.

"We haven't seen this short of a holiday season since 2013, when e-commerce sales at that time was probably less than half of what what they are today," Cathy Roberson, president of Logistics Trends & Insights, explained to ABC News.

But major shippers said they have been preparing for this all year long.

FedEx said it has worked closely with major retailers to forecast surges in shipments while UPS has expanded its footprint with six new hubs to rapidly sort packages.

Amazon has also staffed up their fulfillment centers with over 300,000 full and part time associates to handle the holiday chaos.

The U.S. Postal Service said that it expects to deliver 800 million packages this holiday season with 28 million per day the week prior to Christmas.

To bolster their efforts the USPS said they have added seasonal staff as well as enhanced technology to help get the job done.

"Customers that are shopping either online or in stores for that matter, should probably do it as soon as possible," Roberson urged in order to ensure people get packages on time.

Key Dates and Cutoffs for Ground Delivery

If you want that present to be under the tree in time by way of ground delivery, here are the last days to send shipments with major carriers.

UPS: December 13
USPS: December 14
FedEx: December 16

Beyond that, prepare for the possibility of expedited shipping fees.