At what weight does First-Class mail become Priority Mail?

First-Class Mail becomes Priority Mail at a weight of 13 ounces. This weight threshold is important for understanding how mailing options are categorized within the United States Postal Service (USPS) system. First-Class Mail is designed for lightweight and time-sensitive items, whereas Priority Mail provides expedited delivery services with additional benefits such as tracking and insurance.

When a package exceeds the 13-ounce limit, it transitions from the First-Class category to Priority Mail, which accommodates heavier items and offers faster delivery times, usually within 1-3 business days. This distinction is crucial for businesses and individuals who need to choose the most appropriate mailing service based on the weight and urgency of their shipment. In this context, the other options represent weights that do not meet the threshold for Priority Mail, reinforcing the correct answer as the point at which the mailing service diverges based on weight.