The Ultimate Postcard Size Guide

When you're mailing postcards, determining the right size can be tricky. The most standard postcard size is 4" x 6", which meets USPS postcard regulations and is affordable to print. However, many people choose to mail different sizes than the 4" x 6". Here's the reasons why, and how you can make the best decision for printing and mailing postcards.

Standard Postcard Sizes

The most common sizes for postcards are 4” x 6”, 5” x 7”, 6” x 8”, 6” x 9”, 6” x 11” and 8.5” x 11”. U.S. Press offers all of these sizes on our postcard pricing page.

Mailable Postcard Sizes

All of the above sizes are mailable (they meet the USPS minimum size of 3.5” x 5.5”); however, not all postcards cost the same to mail. Aside from printing cost differences, different sizes also mail at different postage rates:

  • 4” x 6” postcards mail at the First Class Postcard rate

  • 5” x 7”, 6” x 8”, 6” x 9”, and 6” x 11” postcards mail at the Standard Letter rate or the First Class Letter rate

  • 8.5” x 11” and larger postcards mail as Flats, which are subject to higher postage rates

Understanding Mail Classes and Size Classifications

Mail classes determine how quickly recipients will receive your postcard. The two primary USPS classes of direct mail that drive different postage costs and delivery times are First Class Mail and Standard Mail (now known as Marketing Mail):

  • First Class Mail offers a quicker delivery time (1-5 days), but is generally more expensive.

  • Standard Mail is slower (3-14 days), but is generally less expensive.

The two main size classifications for direct mail postcards are “postcard” size and “letter” size:

  • To qualify as the technical “postcard” size by USPS, your piece must be at least 3.5” x 5”, but no larger than 4.25” x 6”, and rectangular in shape.

  • To qualify as the “letter” size by USPS, your piece must be larger than 4.25” by 6” but no larger than 6 ?” x 11.5”, and rectangular in shape (So, if your postcards fall into this range, the Postal Service classifies them as letters, not postcards. Yes, we know this is confusing. We don’t make the rules, though.)

Quick note: USPS also has thickness requirements for postcards and letters to prevent thin sheets of paper from getting jammed in their machines. However, when you print with U.S. Press, all of our postcard stocks already meet these requirements, so you don’t have to worry about this part. 

The exact postage amount for your campaign will depend on a variety of factors, but as a simple rule, you can estimate costs based on the size of your postcard (postcard vs. letter classification) and the corresponding mail class it falls into.

4” x 6” Postcards: The Most Affordable Option

4 x 6 postcard

4” x 6” postcards fall within the parameters of the USPS “postcard” size rule, and by default, postcards of this size will mail as First Class pieces. (Marketing Mail does not offer lower postage costs for this size, so it doesn’t even make sense to consider this mail class. Why pay more for a slower delivery, when USPS offers a good deal on first class postage for this size?)

As mentioned earlier, First Class mail has a huge benefit: it arrives faster than Marketing Mail. The delivery time for First Class Mail is 1-3 days locally, and 2-4 days nationally. As a bonus, you can receive address forwarding and return services at no additional charge.

Now, let’s talk about how the costs break down:

  • If you mail less than 500 pieces, the First Class rate for postcards of this size is 35 cents.

  • However, if you mail more than 500 pieces, your campaign will qualify for the First Class presorted postcard rate, which means the postage cost drops to an average of 27-30 cents per piece.

Thus, the 4” x 6” is commonly known as the most standard size for a postcard because it qualifies for the First Class, postcard size postage rates, which means fast delivery and low postage costs. Something else to think about: 4” x 6” postcards are also less expensive to print than larger postcard sizes.

The reason is then obvious why this size is so popular: it’s the most affordable option to print and mail, and is a great way to reach your customers without overspending on a direct marketing campaign. 

6” x 8” Postcards: A Happy Medium Between Savings and Impact

6 x 8 postcard

4” x 6” is a useful standard in the world of postcards, but often marketers will want a bigger size to stand out in the mailbox. A good choice in this instance is a 6” x 8” postcard. This size is larger, but still on the lower end regarding printing costs.

Due to its larger size, this postcard automatically qualifies for letter rates. If you mail less than 200 postcards, the postage cost is 55 cents per piece. Ouch!

However, just like the 4” x 6” postcards, you can save money on postage by mailing a bulk quantity:

  • If you mail more than 200 pieces, your campaign will qualify for the Marketing Mail class, which is approximately 30 cents for postcards of this size.

  • If you want to upgrade to First Class in order to have a faster delivery speed, then you’ll need to mail more than 500 pieces. The first class postage rate for 6” x 8” postcards is approximately 39 to 44 cents per piece.

When you’re looking to save on printing and postage but want something larger than a 4” x 6” card, this is the size we recommend because it’s a happy medium between savings and impact. For this size, it makes the most sense to mail a bulk quantity (more than 200 pieces) and choose the Marketing Mail class (albeit slower delivery) to maximize your postage savings.

6" x 11" Postcards: Big Impact and the Most "Bang" for  Your Postal Buck

6 x 11 postcard

Another common size for postcards is 6” x 11”. This is a popular size for campaigns requiring a large postcard to effectively convey a business’s message, but it’s a size that remains cost-effective by staying within the letter rate category for postage. (Anything larger than this size jumps to flat rate postage, which can become quite expensive unless you’re mailing EDDM cards. More on this later.) In fact, postage is exactly the same for postcards of this size as it is for 6” x 8” cards:

  • If you mail more than 200 pieces, your mail will qualify for the Marketing Mail class and receive postage at approximately 30 cents per piece.

  • If you mail more than 500 pieces, you have the option to upgrade to First Class for approximately 39 to 44 cents per piece.

Therefore, the only difference in costs between the 6” x 8” and the 6” x 11” is the printing cost.

While this size incurs more printing costs than smaller cards, the 6” x 11” offers the most impact and is nearly impossible to miss in the mailbox. Since it’s the largest standard size eligible for letter-rate postage, it also means you’ll get the most “bang” out of your postage budget--and likely a higher ROI. 

While these three are the most common sizes for postcards, there is an additional class of mail that affects what size you can choose: Every Door Direct Mail.  

EDDM Sizes: 6.25" x 9", 6" x 11", 8 1/2" x 11" and 11" x 14"

Every Door Direct Mail (EDDM) is a USPS mailing service separate from First Class and Marketing Mail that offers steep postage discounts (approximately 19.1 cents per piece). Unlike First Class and Marketing Mail, EDDM allows you to mail to customers without a specific mailing list. Instead, you’ll select an entire carrier route within a specific geographic area to deliver to, and mail to every resident on that route.

Just like the other classifications of mail, EDDM has specific size requirements: postcards must be at least 6.125” tall or longer than 10.5” and smaller than 12” x 15”. 

Because of these restrictions, there are four common EDDM postcard sizes: 6.25" x 9", 6” x 11", 8.5” x 11”, and 11” x 14”. While the 6".25" x 9" offers the lowest printing cost, the 11” x 14” offers the most impact. You can choose which size makes the most sense for your company. 

EDDM is a popular and cost-effective method to mail postcards intended for geographically focused marketing campaigns. Here’s more information on EDDM to decide if this is the right fit for you.

Custom Postcard Sizes:

Of course, standard sizes aren’t always the best fit for your business’s marketing campaign. U.S. Press can print custom postcards to meet the needs of your business. Simply call and speak to one of our account reps at 800-227-7377 for details on custom sized postcard printing.

Regardless of postcard size, there’s a way to increase savings and reach your customers more effectively. U.S. Press is ready to fulfill your direct mail order to help you connect with your customers in a fast and cost-effective way.