What Sizes Does Direct Mail Come In?

Direct mail company

When planning a direct mail campaign, you have a few decisions to make. Before starting the design or content, you have to know how much space you’re working with. How big will your direct mail piece be?

The direct mail marketing experts at Epsilon Individual Automotive are here to help you learn more about sizing options for your next direct mail campaign.

Postcard Sizes

Post CardOne of the most popular options for direct mail is a postcard. Postcards are small and stand out against standard-size mail, with their size and coloring not hidden by a traditional white envelope. Postcards are a great opportunity to use bold photos, colors, and fonts that are easy to read and look at but still stand out.

The standard USPS postcard size is 5 inches long by 3.5 inches wide by 0.007 inches thick.

If you want more space on your postcard, you can go up to 6 inches long by 4.25 inches wide by 0.016 inches thick.

Tip for selecting postcards: The right thickness is an important part of creating your postcards. It can be difficult to tell by sight if your postcard is the correct thickness. The good news? An index card is the right thickness. Just compare the two to see if you’ve chosen the right size!

Postcards are commonly used for direct mail campaigns with the goal of communicating:

  • New promotions
  • A new product
  • New service

You can also use postcards for quick announcements about your business.


Letter Sizes

Letters are another option for direct mail marketing. When you create a letter, it must be at least 5 inches long by 3.5 inches wide by 0.007 inches thick. This is the same thickness as the postcard requirement.

These letters typically fit into a standard No. 10 envelope. However, you can create custom-sized envelopes for letters that are a little bit bigger, though they must still meet the letter dimensions to ship at a letter price.

The largest a letter can be is no more than 11.5 inches long by 6.125 inches wide by 0.25 inches thick.

Letters are typically seen as the classic direct mailer. Letters often include a letter or flyer with information, as well as a response form inside the envelope. Fundraisers or surveys are commonly sent out via letter, although these days, you can also use QR codes to direct a consumer to an online survey.

Every Door Direct Mail® Sizes


Every Door Direct Mail® (EDDM®) is a service to deliver your direct mail through the USPS to your local community. You can select zip codes and neighborhoods or filter by more specific demographics using U.S. Census data.

You can choose a variety of sizes for EDDM® campaigns, although the three most popular are postcards, oversized postcards, and tri-fold menus whose dimensions are:

  • Postcards: 6.5 inches by 9 inches
  • Oversized postcards: 8.5 inches by 11 inches
  • Tri-fold menus: 4.25 inches by 14 inches

EDDM® allows you to send up to 5,000 mailers a day, although you must keep the weight of your mailers under 3.3 ounces each. No postage permit is required for EDDM®, and instead of printing names on your mailers, they will be addressed in the EDDM® format.

If EDDM® is not the right option for your direct mail campaign, consider commercial or bulk mailing options from the USPS. These options come with the other sizes we discuss on this page.

Flats and Oversized Mail Sizes

The last category of direct mail is flats. Flats can include magazines, newsletters, brochures, and other oversized mail pieces. Many people enjoy exploring the catalogs they receive in the mail, establishing brand awareness, and they help to create a relationship between you and your customers.

The minimum dimensions of flats are 11.5 inches long by 6.125 inches wide by 0.25 inches thick.

The maximum dimensions for flats are 15 inches long by 12 inches wide by 0.75 inches thick.

Flats and oversized mail pieces can be several kinds of direct mailers, such as:

  • Brochures or Catalogs
  • Dimensional Mailers
  • Product samples

Brochures and catalogs are a great option for promoting new products or inventory, such as the vehicles in your showroom. Inserts can be included in these brochures with specials or current promotions.

Dimensional mailers often make use of pop-ups or 3D elements in the design. These stand out and are often used for targeted campaigns, fundraisers, or exciting announcements.

Which Direct Mail Size Has the Best Response Rate?

Direct MailDirect mail, in general, has a high response rate of 9% for house lists!* The combination of technology and direct mail has created a great way for marketers to gather more data on consumers and measure the success of their direct mail campaigns. Then, they can tweak the next one for an even better return on investment.

So, how does each size of direct mail perform in terms of response rates? Take a look*:

  • Letter-sized envelopes have a 3.5% response rate.
  • Catalogues have a 3.9% response rate.
  • Dimensional Mailers have a 4% response rate.
  • Postcards have a 4.25% response rate.
  • Oversized Envelopes have a response rate of 5%.

Oversized envelopes have the highest response rate because of the way that they stand out when people go to get their mail. Postcards stand out for similar reasons. These unusual sizes grab attention from the beginning because they feel different when being held.

If you want to measure the response rate of your direct mail campaign, consider using technology as part of your mailer. QR Codes and personal URLs (PURLs) can be personalized and added to your direct mailers. These can lead your customer to a landing page that directly addresses their needs and aids them in taking the action you want them to take.

Start Planning Your Next Automotive Direct Mail Campaign Today

With all the sizing options available for direct mail, you can create the automotive campaign that fits your vision.

If you’re ready to get started, the team at Epsilon Individual Automotive can help. From design to data, our team can help you create a campaign that brings more business to your dealership and helps you get more drivers behind the wheel.

Contact us to get started today.


* https://www.smallbizgenius.net/by-the-numbers/direct-mail-statistics/#gref