what is first class mail rate refers to the cost of sending letters, small packages, and lightweight items via USPS’s First-Class Mail service. When users search for “what is first class mail rate,” they are typically looking for information about the current rates for sending mail via USPS’s most affordable service. First-Class Mail is ideal for sending letters, postcards, and small parcels, offering one of the lowest-cost options available through USPS. Rates start at $0.66 for a single-piece letter weighing up to 1 ounce. Additional weight increases the cost, with a maximum weight of 13 ounces. First-Class Mail provides fast delivery, typically arriving within 1 to 5 business days, depending on the destination. It is an affordable choice for individuals and businesses looking to send lightweight mail or packages with a reliable and relatively fast delivery time.