Postal Regulations for Postcard Mailing

How to Correctly Mail a Postcard by USPS Regulations

Postcard mailing is an inexpensive form of mail advertising with short and instant messages, large areas for visual graphics, that can come in an array of sizes. Postcards include clear calls to actions that entice people to buy products or attend events. They are also a cheaper route for mailing because they do not need an envelope to mail. So, at least virtually, a postcard is always seen and read! But to correctly and effectively mail a postcard you must stick to the postal regulations for postcard mailing set forth by the United States Postal Service (USPS).

If your postcard is not respecting these conditions for size and thickness, it will be considered a letter and you’ll have to pay large envelope postage prices.


Postal Regulations For Postcard Mailing


Below is a short list of the main postal regulations for postcard mailing. Run through the checklist of points to consider when you are mailing a postcard:

Postal Regulations for Postcard Mailing

Postcard size and thickness

According to the USPS website, your postcard must be:  

  • At least 3.5 inches high by 5 inches long and at least 0.007 inches thick
  • No more than 4.25 inches high by 6 inches long and 0.016 inches thick.
  • A postcard must be rectangular.

If you are not sure if your postcard is thick enough, contact a direct mail expert that has tools for precisely measuring thickness and can tell you if your mailpiece is thick enough.

Slim postcards have the tendency to be caught into the mailing processing equipment, and that is likely to result in damaged mailers.

Odd-shaped postcards, (square or thin and long) will cost even more to mail than just large, rectangular postcards. So, to keep it under the budget, choose rectangular postcards.

See A Customer’s  Guide to Mailing by USPS, January 2018. 

Barcode Area

Leave a barcode area as well as a mailing address area and a mailing permit area which are non-printable parts of the postcard.

The barcode area dimensions require 5/8 inches by 4 3/4  inches in the bottom right corner of the postcard.

The mailing address

The mailing address dimensions require (depending on the postcard dimensions) anywhere from 3 1/2 inches to 4 1/4 inches to 4 3/4 inches long and the mailing address is right above the barcode area on the right side of the postcard.

The indicia

The Mailing Permit area designated for the indicia includes a small box in the top right corner with 4 lines:

  1.  Class Marking
  2.  The words “U.S. Postage Paid”
  3.  City and state where the permit is held
  4.  The word Permit and your permit number

Mail Classes

There are multiple different mailing classes to choose from when you are mailing a postcard but it comes down to whether you are a non-profit or not, how many pieces you want to mail, and how much you are willing to pay to get it out quickly. The most commonly used mailing classes are First-Class and Priority Mail. You can choose from:

  • Priority Mail Express
  • Priority Mail
  • First-Class
  • USPS Marketing Mail
  • Non-profit (must be an established non-profit organization with mailing permit)

Read more about picking a mailing class.

The difference between direct mail formats will reflect in your mailing budget. For example:

  • First-class postcard rate: $0.35
  • First-class letter rate: $0.50 (35% more expensive)
  • Odd shaped rate: $0.64 (58% more expensive)

So, let’s say you have to mail out 1,000 postcards for your business, then mailing at a postcard rate will save you $150. But, if you want to send fancy postcards and make them perfectly square, you’ll end up paying $640 instead of the basic $350 just for the stamps.

EDDM route

Postcards are an affordable and effective method of mailing whether you use a targeted mail drop or an EDDM. Finding out the route that allows for the best return is the key to a successful EDDM campaign. That means you should plan out carefully the area you are going to advertise to, knowing why that area is your ideal target.

If it doesn’t have the correct size or indicia, or if it doesn’t have a clear and to-size address and the barcode area, the mailing will not reach its intended target. More than that, you will have to pay extra postage penalties.  

Accurate Mailing Services is always available to help you design, print, mail, or just discuss your project. It is better to be well prepared and understand the regulations of a postcard mailing rather than lose money on an unsuccessful attempt.

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