According to the United States Postal Service, mail under 13 ounces takes two to three business days when shipped by First Class and Priority classes. When shipped Priority Express class, mail is delivered the next day.
Mail that is shipped by Standard Post and Media Mail classes arrives in two to eight business days. The Standard Post class is used when delivery time is unimportant or when shipping oversized boxes not exceeding 130 inches. The Media Mail class is used for shipping educational items such as used books. These timeframes are for deliveries made within the United States.
The USPS uses FedEx for international shipments made by the Global Express class, and these shipments take one to three business days. Priority Mail Express International takes three to five business days to arrive. Priority Mail International takes six to 10 business days.