USPS Delivery Timeframes
Note: First class mail does not include tracking information. If you need to track your letters, you'll need to send them via Certified mail.
A USPS First-Class letter should be delivered within 3 - 5 business days. A business day is considered Monday through Friday, not counting postal holidays.
Certified Mail is an added service to First-Class mail and should arrive at the destination in 3 - 5 business days as well. However, if you requested a signature, the process could take longer if no one is around to accept the letter.
Keep in mind that the USPS does not offer service guarantees on First-Class or Certified letters. We are aware that some letters never arrive, albeit an extremely small percentage. We are also aware that some letters take much longer than 3 - 5 days to arrive, especially since COVID-19 started. That topic is discussed more here.