The clock is ticking. There's just over a week left before Christmas, and even less time to get your packages in the mail if you want them to arrive in time on Dec. 25.

The United States Postal Service expected 830 million cards, packages, and letters to be entered into the mail system on Monday alone. That's 300 million more pieces or 40 percent more than the average daily volume.

People arrived well into the night at the Midway Post Office Monday night eager to get their Christmas mailings in on time. A steady stream of cars pulled up to the drive through mail boxes long after the counters closed down for the day. The postal service will guarantee Christmas delivery if items are post marked by Wednesday, December 16th.

United Parcel Service here in San Diego told Fox 5 by phone it has accepted about 50 percent more items for shipping during the last week alone. UPS will guarantee Christmas delivery to the east coast if your packages are dropped off by Wednesday December 16th and packages to the west coast if they are dropped off by Friday December 18th.

FedEx also reported Monday, December 14th the busiest shipping day of the year as well. The Memphis based company said it expected to accept about 13 million pieces which is about one million more than the typical business day. FedEx will guarantee Christmas delivery as long as your packages arrive at one of its drop off locations by Monday, December 21st.