Though U.S. Postal Service delivery time varies depending upon destination and type of service, First-Class Mail, commonly used for letters and small packages, is usually delivered within two to three business days. This service is appropriate for mail up to 13 ounces in weight.
Priority Mail, used for packages, is delivered within one to three business days, depending upon starting point and destination. The Priority Mail Express service guarantees overnight delivery of letters and packages to most U.S. addresses. Standard Post, intended for non-urgent packages, typically takes two to eight business days. Educational materials sent through Media Mail are also delivered within this time frame.