FORT WAYNE, Ind. (WOWO): If you’re mailing a Christmas gift or two, you’ll want to get to the post office today or tomorrow.

The US Postal Service says December 19th is the deadline for mailing a package or Christmas card via First-Class Mail if you want it to get there by Christmas Eve.

If you’re using Priority Mail, that buys you an additional day, with the deadline for that service set at December 20th.

The U.S. Postal Service will deliver more than 15 billion pieces of mail this holiday season, including more than 850 million packages, with this week traditionally being the busiest time of the year for postal workers.

Mail carriers will also deliver packages on Christmas Day, but only in select locations.