usps how long will it take to deliver depends on the specific service used, the destination, and the time of year. USPS offers several delivery options, including First-Class Mail, Priority Mail, and Priority Mail Express, each with different delivery times. First-Class Mail typically takes 1-3 business days for domestic delivery, while Priority Mail can take 1-3 business days, and Priority Mail Express guarantees next-day delivery. Delivery times may be longer for international shipments or during periods of high volume, such as holidays.