priority mail usps how long Priority Mail USPS typically delivers packages within 1 to 3 business days, depending on the destination. This expedited service is one of the most popular options for both personal and business shipping needs, offering fast and reliable delivery with tracking and insurance included. For most domestic deliveries, Priority Mail guarantees delivery in 1 to 3 days, although times may vary slightly depending on factors like weather or holidays. This service is ideal for those who need faster delivery than standard mail services.