USPS typically delivers a First-Class Mail letter within 1 to 5 business days, with about 70-75% of such mail arriving within three days or less. This 1-5 day range remains the official service standard as of 2025, despite some refinements and adjustments to delivery expectations based on ZIP code pairs
. While USPS recommends allowing up to five to seven business days to account for occasional delays, most letters arrive sooner, especially if sent within the same region or state. Delivery times can be affected by factors such as distance between sender and recipient, holidays, and operational constraints
. In summary:
- Standard First-Class Mail delivery time: 1-5 business days (most within 3 days)
- USPS does not guarantee exact delivery times but aims to keep mail delivery within this range
- Delivery may be slower during peak holiday seasons or due to operational changes
- USPS does not deliver First-Class Mail on Sundays
For more precise delivery estimates, USPS provides tools online that calculate expected delivery times between specific ZIP codes based on current service standards
