What you need to know about mail sizes


Ready to start mailing pieces but overwhelmed by all the different mail sizes and information out there? Don’t worry, you’re not alone. There’s a lot to know when you’re getting started but we want to make sure you have everything you need to send mail pieces that are cost effective and useful to your business and customers.


Mail formats

One of the first things you need to know about when it comes to mail sizes is the different mail formats. These two items go hand in hand because picking a mail format in a particular size could help you save money in the long run. So, what exactly is a mail format?


According to McCarthy and King, a direct mail format refers to a specific type of mailer, which is either an envelope mailer or a self-mailer. An envelope mailer is your typical piece of mail in an envelope and a self-mailer is a self-contained mail piece that requires no envelope.


There are a lot of different mail formats, and all of them are different sizes to help serve a different purpose. You’ll find postcards, slim jim’s and digests, just to name a few. Let’s dive a little deeper into these formats.



By definition, a postcard is a card that’s used for sending a message by mail without an envelope, and typically include images and text. You’ll find multiple sizes of postcards including small, tri-fold, bi-fold and small bi-fold. With a bi and tri-fold, they’ll still be sent without an envelope but they will require a seal to hold them together.



This is formatted similar to a magazine. It’s smaller than a standard magazine but larger than a standard book. This will provide you with plenty of space to promote your business or products.


Slim Jim

According to USPS, a Slim Jim is considered a booklet, which means you have room to get the correct information out to your customers. The compact size allows you as a business to save on postage and paper costs. The compact feel also allows for a more personal feeling - especially if you focus in on your design and photos. 



A publication piece gives way to a lot of valuable space in a smaller magazine format. You can have anywhere from 8-64 pages in your publication, which will allow you to get a lot of information out about your company or product. With the option of having so many pages you could have a lot of pictures or text showing your product, you could even use space for coupons.


There is also a self-mailer publication, since there’s no need for an envelope, you’d save money in the long run.


You can check out our REACH Mail Formats Comparison Chart to see how different formats compare and to see which would work best for your businesses needs.


REACH Formats Comparison Chart

Get the comparison chart


How can you save on postage with the right mail size?

You know a few of the different mail sizes, but did you know picking the right one for your project could save you money? Postage can account for over 50% of a direct mail campaign, so picking the right mail size can help cut that cost down.


Work with a printer early on

This is where Aradius Group comes in! One of the best things you can do when starting your direct mail campaign is working closely with a printing company from the beginning. It will allow them to make sure you’re on the right track and give advice from start to finish. If they know what you’re looking to do, they can help make sure you get the best product and the best rates.


Know when rates change

It’s important to make sure you’re staying on top of when rate changes happen. You may have something budgeted at one price, just to realize the price has increased, and then you have to move things around in your budget. You’ll find that carriers review pricing every year and adjust rates to make up for things like fuel and labor.


Working closely with a printing company will also allow you stay in the know about rate changes, they’ll make sure you know when they’re changing so you can plan accordingly.


Know about different sizes and mail formats

There are so many mail formats you could choose when doing a direct mail campaign, but picking the right one will save you money in the end. Aradius Group has done the hard work for you by creating REACH, which takes some of the most popular mail formats and creates them with dimensions that are just slightly off the most cost effective size. Implementing this solution will allow a company to save on production time and postage costs.


How REACH works:

  • First, download our REACH Overview to see our recommended formats and sizes, then connect with our team. They’ll be able to help you understand which cost saving format best suits your direct mail piece.

REACH optimized direct mail options:Postcard, slim jim, digest, bi-fold, landscape, publication, self-mailer

  • Next, now that you’ve chosen the best format for your project, we can give you a quote on your project based on your selection and your team can start designing. You can check out our REACH InDesign Templates as a starting point.
  • Finally, when your design file is complete, check to make sure it follows our Prepress File Guidelines, then send it over to our team!

After all of that is done, we’ll schedule it, move it to production and then mail the pieces to their final destination! 


Check out our other resources to see what else we have to offer to help you plan and design your next mailpiece:

Get the Mailpiece Design Guide



Get the Checklist


The takeaway

There’s no reason to be in the dark when it comes to different mail sizes, and there’s absolutely no reason spend 50% of your budget on postage. Finding the right mail size requires extensive research, but in the end it pays off to save your company money and get the right pieces to your customers. By doing this work on the front end you’re setting your business and campaign up for success.


If you’re interested in learning more about mail sizes, REACH out! Aradius Group would love to help in any way.