Standard Postcard Sizes: Which Ones Are Mailable?

Mailing postcards helps get your message across to your audience. However, choosing the right size is important so they fit in the mail and won't get wrinkled while in transit. But how do you know which sizes are mailable or not? Read on as we go over the different standard postcard sizes and the many ways you can mail your postcards.

What Are the Standard Postcard Sizes?

If you’re unsure which postcard size to choose and which suits your needs best, let this chart help you decide.

Size	Mail Eligibility	Best Used For
3.5" x 8.5"	First-Class, Standard Letter	Event invitations, business announcements, promotions
4" x 6"	First-Class, Standard Letter	Personal greetings, promotional materials, invitations, and more
4" x 9"	First-Class, EDDM, Standard Letter	Promotional materials, menu highlights, invitations, travel destinations, real estate listings, or panoramic artwork
4.25" x 5.5"	First-Class, Standard Letter	Advertising, showcasing products or highlighting special offers
4.25" x 6"	First-Class, Standard Letter	Handing out at trade shows, sending out announcements, promoting new products and services
5" x 7"	First-Class, Standard Letter	Showing product images, detailed promotions, special events
5.5" x 8.5"	First-Class, EDDM, Standard Letter	Image-heavy content, introducing brands, event promotions
6" x 8"	First-Class, Standard Letter	Creative events, art exhibitions, specialty products, and brand storytelling campaigns
6" x 9"	First-Class, Standard Letter	Promotional materials, product showcases, event programs, and informational guides
6" x 11"	First-Class, EDDM	Panoramic images, detailed messaging, and large designs
8.5" x 11"	First-Class, Standard Letter	Marketing materials, product catalogs, event promotions, and product launches

3.5" x 8.5"

This tall and slim postcard shaped like a bookmark lets you present information uniquely and stands out in the mail. An ideal postcard size for showcasing panoramic images, displaying tall products, or conveying vertical designs. Use this postcard size for real estate promotions, event schedules, menus, service lists, or special offers.

4" x 6"

The 4" x 6" postcard is the most popular size in the US. It is convenient and compact enough to fit into most envelopes and mailboxes easily. This postcard size is ideal for personal greetings, promotional materials, invitations, holiday greetings, or simple announcements because it has ample space for impactful visuals and concise messaging. It's also suitable for direct mail campaigns and can be displayed in racks or retail stores. Additionally, postcards of this size qualify for First-Class Mail pricing, which makes them an affordable option, especially if you are sending out bulk postcards.

4" x 9"

Longer than standard postcards, this size is perfect for event invitations, business announcements, and promotions. Its shape lets you get creative with panoramic or landscape-oriented layouts and impactful visuals, giving you more room for long messages, pictures, and important details you want to highlight. It's great for showcasing scenic views, architectural photography, or any content that benefits from a wider format. This size works well for promoting travel destinations, real estate listings, or panoramic artwork. Tourist boards, travel agencies, or photographers often use these to showcase picturesque locations.

4.25" x 5.5"

Slightly larger than average, this size is ideal for advertising limited offers or new products. It can be used in direct mail campaigns, distributed at trade shows and networking events, or included in product packaging. Provides enough space for impactful visuals and essential information while remaining cost-effective for printing and postage. The unique size would grab attention among standard-sized mail.

4.25" x 6”

Like the 4.25" x 5.5" size, this postcard offers a compact yet noticeable canvas for advertising, promotional offers, event promotions, product launches, and upcoming sales. With slightly wider dimensions, this size provides more space for content and imagery, additional text, and interactive elements while remaining budget-friendly for printing and distribution.

5" x 7"

This medium-sized postcard has the perfect balance for impactful visuals and detailed messaging. This size suits special announcements, invitations to upscale events, or showcasing premium products or services. We recommend this size for luxury brands, event planners, or upscale businesses, as it will make a lasting impression.

5.5" x 8.5"

This size offers a wider format, allowing room for eye-catching visuals and detailed information. It's great for sending marketing materials showcasing product collections, portfolio samples, or detailed event agendas. Businesses that want to make a bold impression often use this size for marketing purposes. Additionally, it's effective for sending out invitations to exclusive events or VIP promotions.

6" x 8"

A square-shaped postcard with wider dimensions. This size effectively showcases square images, artistic designs, or unconventional content layouts, making it suitable for promoting creative events, art exhibitions, specialty products, and brand storytelling campaigns. Artists, designers, or creative agencies use this size to showcase their work in a visually striking format. It's also effective for promoting art galleries, museums, or cultural events.

6" x 9"

6" x 9" postcards are known for being large and oversized. This size is perfect for promotional materials, product showcases, event programs, and informational guides. Its dimensions offer ample space for large images, detailed messages, and various content types while still being easy to handle and mail.

6" x 11”

With its oversized dimensions, this postcard is excellent for presenting panoramic images, detailed messaging, and large designs. You can use this to promote luxury travel destinations, high-end real estate listings, or premium lifestyle brands. If you want bigger, bolder promotions, this size is for you.

8.5" x 11"

The largest size on the list, this postcard is used for marketing materials, product catalogs, event promotions, and product launches. It provides enough room for expansive layouts, detailed descriptions, and high-resolution images.

Different Ways You Can Mail Your Postcards

How do you know which mailing option is right for you? Here are different ways you can mail your postcards.

First-Class Mail is the fastest option if you want your postcards to get to your recipients in 1-3 days. This option also provides a return and forwarding service for free. Choose this mailing service for sending individual postcards for personal correspondence, invitations, or urgent marketing campaigns. Your postcards should also be rectangular and must have a minimum size of 3.5” x 5” (must be 0.007” thick) up to 4.25” x 6” (must be 0.016” thick) to qualify for First-Class Mail.

Standard Letter or First-Class Letter may not be as speedy as First-Class Mail, but it’s still cost-effective if your promotions are not as time-sensitive. The estimated time for delivery for this option is 5-15 days, depending on whether the postcards are mailed locally or nationally. This mailing option is suitable for bulk mailing postcards for advertising, promotional campaigns, or informational mailings because it offers discounts and affordable rates. When choosing Standard Letter, make sure that your postcards are rectangular and have sizes of at least 4.5” x 6” up to 6” x 11.5”.

EDDM, or Every Door Direct Mail, is a mailing option that requires specific mailing routes or ZIP codes. This is very useful if you want your postcard advertisements to reach every household or business within a specific geographic area without the need for mailing lists or addresses. Keep in mind that for your postcards to be eligible for EDDM, they should be at least 6.125” x 10.5” or 0.25” thick up to a maximum size of 12” x 15” or 0.75” thick and should weigh less than 3.03 ounces.

To ensure that the USPS correctly handles your postcards, it’s also important to follow the proper mailing regulations so that your postcards are delivered without delays and won’t incur additional charges.

When printing postcards, picking the right size does matter. This can help you communicate your message effectively and avoid mishaps during printing and mailing. Remember to use our quick guide and follow USPS' requirements so that you can create postcards that captivate your audience and leave a lasting impression.

Need tips to design your postcards? Check out our article on the best practices for postcard design. For a fuss-free design experience, we also recommend using our free design templates.

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