The United States Postal Service (USPS) delivers most mail packages fairly quickly. However, most people do not realize that in almost all cases, delivery times are estimated and not guaranteed. This means it's not possible to sue the USPS for failing to deliver first class mail or priority mail within the estimated three days for most locations.

Here are the estimated delivery times for the US Postal Service:

  • Domestic Priority Mail - usually 2-3 days estimated
  • Domestic 1st Class Mail - usually 1-3 days estimated
  • Domestic Parcel Post - usually 2-9 days estimated
  • Military First Class Mail - 7-10 days (estimate by MPSA - Military Postal Service Agency)
  • Military Priority Mail Parcel - 10-15 days (estimate by MPSA - Military Postal Service Agency)
  • Military Parcel Post - 24 days (estimate by MPSA - Military Postal Service Agency)
  • International Priority Mail - 6-10 business days estimated
  • International First Class - varies depending on destination
  • Bound Printed Matter or Media Mail - may be estimated when postage is calculated

For example, if a priority mail package is estimated for two day delivery but takes three weeks to arrive, there is no way to get compensation from the US postal service for the late delivery. Delivery standards for all postal service products other than Express Mail are estimates but they are not delivery guarantees.

The only way to get a guaranteed delivery time is to purchase the US Postal Service's Express Mail product. Even if you need a package to arrive on the opposite coast within a week rather than within a day, there is no guarantee that it won't be late unless it's Express Mail. International Express Mail is not guaranteed except for select destinations. Express Mail is the only product that has the ability to track a package along the way.

Here are the guarantee delivery times for the US Postal Service when using Express Mail:

  • Domestic Express Mail - guaranteed 1-2 days (by noon or 3pm)
  • International Express Mail - 3-5 days estimated (guaranteed only to select destinations)

If there are US Postal Service holidays, adjustments to these estimates may need to be made (other than for Express Mail) depending on the service selected.

In short, if a package absolutely needs to get there by a certain time, it needs to be shipped via Express Mail, even if the deadline is two or three weeks away. US Postal Service does not guarantee any delivery time standards for any product other than Express Mail. Keep in mind that the guarantee is limited to getting the money back for postage costs only. It does not include other damage or costs due to late delivery.