To ensure timely delivery of cards, letters and packages within the United States by Dec. 25, the Postal Service recommends that customers ship their items by the following dates:
Mail-by Dates — Domestic Services
Dec. 15 – USPS Retail Ground
Ground service for less-than-urgent deliveries and oversized packages.
Dec. 20 – First-Class Mail
Service for standard-sized, single-piece envelopes and small packages weighing up to 13 ounces with delivery in 3 business days or less.
Dec. 21 – Priority Mail
Domestic service in 1, 2 or 3 business days based on where the package is mailed and where it’s being sent, variety of flat-rate options.
Dec. 23 – Priority Mail Express
Fastest domestic service, guaranteed overnight scheduled delivery to most locations. Some restrictions and exceptions apply. Please note, Priority Mail Express postage refund eligibility is adjusted for shipments mailed between Dec. 22 and Dec. 25.