Sending packages to loved ones? Send them by these dates

It's the most wonderful time of the year. But it can also be the most stressful if you don't plan ahead.

If you're sending holiday gifts to loved ones who live in different places, there are some things you need to know to make sure their presents get there on time.

The busiest mailing day will be Monday, Dec. 14 and the busiest delivery day will be Monday, Dec. 21, with more than 30 million packages being delivered on that day.

Here are some dates to keep in mind when sending stuff around the holidays --

International Shipping: the deadline was Dec. 8, but you can still send packages through priority mail by Friday. Dec. 11, priority mail express by Tuesday, Dec. 15, and global express guaranteed by Monday, Dec. 21.

Military Shipments: the deadline was Thursday, Dec. 10, but you can still send packages through priority express mail by Thursday, Dec. 17.

Domestic Shipping: send packages by Tuesday,  Dec. 15 for standard mail, Monday, Dec. 21 for priority mail, and Wednesday, Dec. 23 for priority express mail.

Cards and Letters: Must be placed in the mail by Saturday, Dec. 19 to arrive on time.

About 15.5 billion packages, cards, and letters will be delivered this year between Thanksgiving and New Year's Eve.