If you're mailing holiday gifts, you better get to the post office soon; deadlines are almost here.

An estimated 2.3 billion packages will be shipped this holiday season, up 5% according to officials.

If you want your gift to be delivered by Christmas, you need to act soon. The U.S. Postal Service's listed deadline to ship ground is Dec. 17, and the 20th is the last day to send a package for two-day delivery.

The last day for two-day shipping at UPS and FedEx is Dec. 22. Both offer overnight service on Dec. 23 for delivery on Christmas Eve.

USPS, UPS and FedEx are all closed on Christmas Day.

If you want to play it safe, make sure all your gifts have been sent by Dec. 15.

And remember, there's no room for error: make sure the address on your packages is correct and provide your email so you can track your package.