First Class Mail is the most economical way to send a package weighing 13 oz. or less (4 lb max for International Mail).  While it is not a guaranteed delivery service, First Class Mail is generally delivered within 1-3 days for mail sent within the continental United States.  Here are some tips and tricks to get the most out of this inexpensive mail class.

Size Matters

While, most mailers are aware that weight affects postage requirements, it is important to note that the USPS charges different prices depending on the size of First Class Mail.

Depending on the length, width, weight, thickness, and aspect ratio (length divided by height), First Class mail is classified as either a Post Card, Letter, Flat Mail/Large Envelope, or a Package.  Because the USPS charges different prices for each of these mail classes, it is important to know which type of mail you are sending.

To help identify your mailpiece’s appropriate mail class, we have developed the following two tools:

Online First Class Mail Classification Tool: This new page contains a complete breakdown of the characteristics for each type of First Class mail.  Includes step-by-step instructions to help determine your mail class.

Shape Based Template: This new product developed by is the easiest way to determine which type of First Class mail you have.  As shown below, simply place your mail piece in the corner of this template and use the color-coded guide to determine your mail class and whether or not it is subject to any non-machinable surcharges.  This tool is available from the Store for only $7.99.


How to send First Class Mail with Delivery Confirmation

Did you know that packages are the only First Class Mail class that can be sent with Delivery Confirmation?  An easy way to turn a First Class mailpiece into a package is to make sure it is at least ¾” thick at any point.  Once a mailpiece is more than ¾” thick, the USPS considers the mailpiece to be a thick envelope which is subject to package rates.  Although packages require slightly more postage than letters and large envelopes, this is the cheapest way to send a mailpiece with delivery confirmation.  For added security, you can also use signature confirmation on First Class Mail packages; if you are a PayPal shipper, this is important as PayPal requires Signature Confirmation for any item over $250 in value.


First Class Mail International – Cheapest Way to Send Internationally

If you are looking to send mail internationally, First Class Mail International is the cheapest shipping method available for items 4 lbs and under.  As an example, a 9-ounce package sent from the US to Italy is only $9.04 with First Class International compared to $12.78 to send the same shipment using a Priority Mail International Small Flate-Rate box.  With, you can print postage for any international mail class, including customs forms.

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