(CNN) - Holiday planners, here's what you need to know if you're using the U.S. Postal Service to send out packages by Christmas Day in the contiguous United States.
The Postal Service recommends that packages are sent no later than Dec. 21, for priority mail express service, which is faster and usually costs more.
Less expensive options, like first-class mail and ground service, must go out by Dec. 18. First class mail must go out by Dec. 18 and the cut-off for ground service is Dec. 16.
A complete list of holiday mailing and shipping dates can be found at USPS.com.