Sending Certified Mail

Getting Started

LetterStream makes it easy to print and send Certified Mail without visiting the Post Office. Certified Mail is a good option if you need to provide proof mailing, and includes USPS tracking information, but it does not guarantee delivery by a specific date.

Before choosing Certified Mail, keep these limitations in mind:

  • Delivery times are only estimates.
  • USPS tracking may contain delayed, missing, repeated, or incomplete scans.
  • LetterStream cannot see information beyond the tracking events USPS provides.
  • A recipient may refuse the letter or fail to claim it.
  • A signature or Electronic Return Receipt may not become available if USPS does not successfully complete delivery and capture the signature.
  • Certified Mail does not include a guaranteed delivery date.

Certified Mail is typically best when the service itself is required, or proof of mailing is required, and these USPS limitations are acceptable.

LetterStream controls the printing, preparation, and mailing of your letter. Once the mailing is accepted by USPS, transportation, tracking scans, delivery attempts, recipient pickup, and final delivery are controlled by USPS.

In This Article

Sending Certified Mail

LetterStream makes it easy to send Certified Mail without leaving your home or office:

  • No need for envelopes, stamps, or printers.
  • LetterStream handles printing, folding, inserting, and mailing.
  • You simply upload your documents and choose your mail type.

For more information on getting started, click here.

Send Certified Mail to a PO Box

Yes, Certified Mail can be sent to a PO Box.

USPS generally places a notice in the recipient’s PO Box letting them know the item is available for pickup. The recipient or another authorized person must then collect the letter and provide any identification USPS requires.

USPS is required to obtain a signature before releasing the Certified Mail item. If Electronic Return Receipt was added before mailing, the available signature record will appear in your LetterStream account after USPS provides it.

If Electronic Return Receipt was not included with the original mailing, it cannot be added afterward and the signature will not be available through LetterStream.

If the recipient does not pick up the letter within USPS’s holding period, it may be marked unclaimed and returned.

Send Certified Mail Internationally

Certified Mail is not available for international deliveries.

For international mail that requires tracking or proof of delivery, the USPS offers Registered Mail:

  • Registered Mail is available through LetterStream.
  • It provides delivery confirmation and tracking, though neither are guaranteed.
  • Be aware: Registered Mail is significantly more expensive than Certified Mail.

For more information, click here.

Maximum Weight Capacity For Certified Mail

Certified Mail flats have a limit of 75 sheets. If your document exceeds this limit, our system will automatically adjust the packaging and delivery method to ensure it is mailed properly.

For example, Priority Certified Mail can exceed the 13-ounce (75-sheet) limit. While this option isn’t available for customers to select directly, our system will automatically detect when a Certified mailing exceeds the limit and upgrade it to Priority Certified Mail, shipping it in a box.

You’ll be notified of this during the job creation process, but no action is required on your part.


Certified Mail is Unpredictable

Certified Mail should be used only when you are required. Certified Mail provides proof that a letter was mailed and accepted by the USPS, but it does not guarantee delivery, signature capture, or clear tracking updates. Delays, missing scans, and incomplete delivery information are common and are considered normal USPS behavior.

Because Certified Mail does not offer delivery guarantees or predictable outcomes, it is not recommended when delivery timing, confirmation, or reliability is critical.

If you are not required to use Certified Mail and want clearer tracking and more dependable delivery confirmation, we recommend FedEx 2Day. FedEx generally provides more consistent tracking, clearer delivery scans, and stronger accountability than USPS Certified Mail.

In short:

  • Use Certified Mail only when required and when USPS limitations are acceptable
  • Use FedEx 2Day when reliability and visibility matter

Once a mailing is handed off to the carrier, LetterStream has fulfilled its responsibility by mailing the letter in good faith, and carrier-related outcomes are outside of our control.