The Ultimate Guide to Direct Mail Sizes and Dimensions

A solid direct mail campaign can help you get noticed and generate leads that would have been hard to acquire with any other marketing strategy. Many businesses use direct mail marketing with much success.

If you are considering implementing this strategy in your marketing efforts, you will benefit from doing your research first. Although, on paper (no pun intended) sending mail to potential customers looks pretty straightforward, there are a lot of factors to consider here.

The first step would be selecting the type of content you wish to mail. And you have a lot to choose from. Postcards, letters, catalogs, calendars, flyers, coupons, and brochures are all popular designs, each with its strengths and weaknesses.

Then, you have to choose the proper size for your direct mail campaign materials. This decision will impact your budget, as well as the overall reception of the campaign. The size should be tailored for the campaign's goals, support your message and fit well within your marketing budget.

Considering the US Postal Service has its requirements regarding the sizes of the mail pieces they can service, it's imperative to learn about the standard sizes of direct mail.

This way, you won't make some costly mistakes, and you'll be able to optimize your operations to fit the objectives.

What Are the Most Common Formats in Direct Mail Campaigns?

The most common formats for direct mail campaigns are postcards and oversized envelopes. They vary in their design, and companies use them for different purposes.

Postcards are great for conveying brief information. You can inform your customers about upcoming sales or promo codes. It can be a very visual-based format, and it's not overloaded with information, which makes it perfect for catching people's attention.

On the other side, we have oversized envelopes, which, according to the Association of National Advertisers (ANA), have the highest direct mail response rate at 6.6%. Oversized envelopes can take various forms - letters in large envelopes, catalogs, or newsletters. They are also known as "flats."

Direct Mail Postcard Sizes

As one of the most affordable and reader-friendly direct mail types, direct mail postcards are often the first format companies, and marketers consider for their direct mail campaigns. They have a solid response rate above 4%, so it makes sense.

According to the USPS requirements, postcards must be rectangular and have specific dimensions.

• Between 3 ½ inches and 4 ¼ inches in height.
• Between 5 inches and 6 inches in width.
• Between 0.007 inches and 0.016 inches in thickness

Anything that doesn't fold under these dimensions USPS might consider a letter rather than a postcard (or consider it a nonmachinable format.) Fortunately, there are many different variants when it comes to postcard sizes. Some of the most common ones would be:

• 4" x 6"
• 4.25" x 6"
• 4" x 9"
• 5" x 7"
• 5.5" x 8.5"
• 6" x 9"
• 6" x 11"

If you want to make this even easier, you can single out the four most common direct mail postcard sizes:

• Small (4.25" x 6")
• Standard (6" x 9")
• Jumbo (6" x 11")
• Extra Large (9" x 12")

Small postcards are considered the standard postcard sizes which means they often are the most cost-effective option. If you do not care much about saving money but wish to outperform competitors, choosing more unique postcard sizes is a good strategy.

The important thing to keep in mind is that it's beneficial to pick the size that will be considered machinable by your post mail provider. This will reduce the costs of your direct mail campaign, as nonstandard dimensions are more expensive to produce and mail, and their delivery time can be longer.

If you choose to send postcards in formats determined by the USPS, you can count on the lower postage rates as well as benefits from first-class mail.

Every Door Direct Mail (EDDM) Dimensions

EDDM is a mailing program created by the USPS and addressed to companies interested in affordable mailing services for their direct mail campaigns. It's an attractive solution, especially for smaller businesses that don't operate on big marketing budgets and may not have the resources to invest in mailing lists.

USPS allows you to use your designs within their sizing guidelines. Here's the list of machinable sizes.

• 4.25” x 11”
• 6.25” x 9”
• 6.25” x 11”
• 6” x 12”
• 8.5” x 7”
• 8.5” x 11”
• 11’’ x 17’’

You can send mail pieces that don't fit these requirements, but it's an additional cost. You can benefit from the USPS' designs, prints, and drop-off services of its affiliates. Still, your materials must meet different terms (in addition to size measurements) regarding placing the address, your logo, or a stamp.

With Taradel's EDDM® mapping tool, you are able to target customers using both geographic and demographic data, which will help you select the best areas for your operations. You can design your mail pieces in five sizes.

• 4.25" x 11"
• 6.25" x 9"
• 6.25" x 11"
• 8.5" x 11"
• 11" x 17"

This way, you're not wasting your time and resources and have the tools to offer your potential customers something eye-catching. If you want to learn more about how you can benefit from the direct mail automation with Taradel, contact us today!

Why Size Matters for EDDM:
Choosing the right EDDM-compliant size ensures your mail qualifies for discounted postage and gets delivered without delay. Oversized pieces stand out in the mailbox — and that added attention can drive stronger response rates for your campaign.

Pro Tip: Use design templates from USPS-approved providers to avoid formatting errors and ensure your mail piece meets all regulations, including the proper placement of the EDDM indicia and address panel.

Direct Mail Letter Dimensions

Similar to postcards, there are a few standard letter sizes to choose from.

• Standard (8.5" x 11")
• Extra Large (8.5" x 14")
• Jumbo (11" x 17")

It might be beneficial to know that according to the USPS, letters can be enveloped, but they don't have to be. Letters are an excellent fit for direct mail campaigns that are intended to update clients about upcoming changes, thank them for their loyalty or offer some insights into how your business operates.

If you want to get personal, a letter is the way to go. And if you care about staying within the norms defined by the USPS, here are the dimensions you should stick to.

• The letters must be rectangular with square corners. If you choose to have rounded (or any other shaped) corners, your mail won't be considered a letter format.
• Letters' sides should be parallel to each other.
• They should have between 3 ½ inches and 6 ⅛ inches in height.
• They should have between 5 inches and 11 ½ inches in width.
• They should have between 0.007 inches and ¼ inches in thickness.

Just like with postcards, if your letters don't fit within these dimensions, they will be considered nonmachinable. In instances when the letters are enveloped, USPS will consider the dimensions of the envelopes instead of the letters themselves.

Enveloped Letters Sizes

There are many options available for direct mail envelopes sizes. The most common are:

• #6 1/4 envelope (3 ½" x 6")
• #6 3/4 envelope (3 ⅝" x 6 ½")
• #7 envelope (3 ¾" x 6 ¾")
• #8-5/8 envelope (3 ⅝” x 8 ⅝”)
• #9 envelope (3 ⅞” x 8 ⅞”)
• #10 envelope (4 ⅛" x 9 ½")
• #11 envelope (4 ½" x 10 ⅜")
• #12 envelope (4 ¾" x 11")
• #14 envelope (5" x 11 ½")

The #10 is the preferred format by various businesses. You can choose the most optimal size for your needs, but you should mind the thickness and weight of your mail materials, as exceeding the previously mentioned limits (max ¼" in thickness and 3 ½ ounces in weight) will increase the postage costs.

One way to stand out amongst competitors is to customize the envelopes. Deciding on different, bright colors and interesting prints could bring more responses than going with standard envelopes types.

Flats and Large-Sized Direct Mail

Flats are a type of marketing mail piece that fits into the category of large-sized mail pieces. These would be magazines, some newsletters or catalogs, and large-sized envelopes. According to the USPS, these direct mail pieces should have dimensions of

• Between 6.125 inches and 12 inches in width.
• Between 11.5 inches and 15 inches in length.
• Between 0.25 inches and 0.75 inches in thickness.

Flats may be more engaging to the recipients, as these direct mail marketing campaign materials offer lots of substance. Of course, designing, printing, and mailing costs are much higher with these formats.

Still, the Direct Marketing Association, in their report, claims that 42% of people read the catalogs they receive in their mail, which is a number worth considering when planning a direct marketing campaign.

Final Thoughts

Choosing the most optimal size for your direct mail campaigns' mail pieces can be challenging, as there are many different options and factors to consider. You must keep the balance between wanting to be noticed by the recipients and your budgetary limitations.

Choosing the designs that best support the campaign's goals is crucial. Certain formats will be more practical for getting new leads, while others will add great value to building your brand's recognition.

With the help of our guide, you can have a better understanding of your options and design a campaign that is aligned with all your objectives.