A Beginners Guide to USPS Postcard Sizes and Rates

United States Postal Service postcard sizes and rates are crucial for scaling the right amount of mail to send out during marketing campaigns. Not only can it save you time and money, but you also want to make sure that this seemingly small detail addresses your target market in the most effective way possible. 

With that said, the various rates and sizes can be confusing if you’ve never dealt with postcards before.

Read on below and discover how many sizes these mailing pieces come in and how much they cost to mail out.

What is a Postcard?

Technically speaking, a postcard is a piece of mail that is rectangular and measures somewhere between 3.5 inches high, 0.007 inches thick, 5 inches in length, and 4.25 inches high, 0.016 inches thick, and 6 inches in length. The radius of the corners must be finished and measure 0.0125 inches or less.

Real Estate Postcard Template
Real Estate Postcard example

USPS Postcard Sizes and Postage Rates

We discuss official postcard sizes below as well as the three main USPS postcard rates.

Standard Postcard size

The most common postcard sizes are considered “standard”, they have a mailing rate of $0.40 and include the following sizes:

  • 3-inches x 4-inches
  • 4-inches x 6-inches
  • 4.25-inches x 5.5-inches
  • 4.25-inches x 6-inches

A standard postcard has a mailing rate of: 

Jumbo Postcards

The next size up from a standard postcard is “jumbo”. These popular postcards have mailing rates starting at $0.55 (equal to mailing a Standard Letter), on up to First Class Letter mailing rates, and are available in the following sizes:

  • 5-inches x 7-inches
  • 5.5-inches x 8.5-inches
  • 6-inches x 9-inches
  • 6.5-inches x 9.5-inches
  • 6-inches x 11-inches

Extra-Large Postcard Sizes and Rates

These days extra-large cards are a thing, and yes, they cost the most to mail out of all the sizes, costing between $0.58 to $1.16. They measure 8.5-inches x 11-inches (or bigger) and have the same mailing rates as “Flats.”

Dashboard for sending direct mail postcards

Why Mail Postcards?

Postcards are mailed for various reasons, including both personal and commercial purposes. It is common practice to send friends and family a little something from the exciting places that we visit, as a way of saying, “I’m thinking of you”.

In business, direct mail postcards are used for a plethora of reasons including sales, press releases on new products/offers, and other marketing purposes. With companies like Postalytics, you can fully automatize postcard marketing campaigns while fully adhering to all USPS requirements.

How to Mail a Postcard

Postcards are the easiest type of mail to send, just follow these easy steps:

1. Add Your Message

If your postcard isn’t a marketing piece and lacks a message, the left side on the back of the card is usually blank just for this purpose. Write your message in this empty space.

2. Address the Card

Add the address onto the card in the correct area. Generally, there is a place reserved for the address on the right side of the back of the card.

3. Attach a Stamp

Place the stamp on the postcard. Typically it goes in the upper right corner, above the intended recipient’s address.

4. Put it in the Mail

Now simply drop the postcard in your mailbox and put the flag up. Alternatively, you may also drop it off in any USPS mail dropbox or take it to the counter inside a local post office branch.

Or save time and money with Postalytics

Discover postcard templates and styling guides that will help you create, send and track any amount of postcards you choose. We’ve partnered with printing companies and automatically adhere to all mailing regulations, so you don’t have to worry whether your postcards are addressed correctly or if they’re being picked up by the postal service.

Finally, get a notification when someone reads your mail. Savvy marketers can use this opportunity to call their leads to further discuss their offers.

FAQs About USPS Postcard Size and Rates

Postcard creator tool

How Much Does it Cost to Mail a Postcard 2024?

Depending on the size, the average cost of mailing one ranges from forty cents to slightly over one dollar. The smaller, thinner, and lighter the card the more affordable it is to mail. 

That said, the measurements have more to do with the cost than the weight does (as nearly all postcards are feather-weight). Standard postcard size cards are the cheapest to mail, followed by jumbo and extra-large.

Do postcards have to be a certain size?

To be considered as a standard postcard, it must be within the dimensions of 3.5-inches by 4.25-inches and no more than 0.007-inches thick. Anything larger than standard postcard size is considered jumbo or extra-large postcards and costs a bit more to send. 

It is important to note that any card over 8.5-inches tall and 11-inches wide are handled as “Flats” and have a higher mailing rate.

Do 5×7 postcards require extra postage?

Postcards that measure 5-inches tall and 7-inches wide fall into the jumbo postcard size category. These 5 x 7 cards cost a few cents more to mail than standard postcards.

What postcard size is most effective?

According to many business owners, the most effective postcard size for marketing campaigns is 6 x 11. These extra-large postcards are sure to stand out amongst the rest of their mail and capture someone’s attention.

Do postcards need special stamps?

Postcards do not need special stamps, rather they use the same standard stamps as most U.S. mail does. For a standard postcard, a single stamp more than covers the cost of mailing. For larger postcards, however, a second stamp is needed. 

Further, extra-large postcards, mailed as Flats, require the third stamp.

Can I mail a 4-inch x 6-inch photo as a postcard?

Believe it or not, people mail photos and homemade postcards in the U.S. every day.

Handwritten mailed postcards are again rising in popularity. Even more, 4-inch by 6-inch photos are amongst the most popular self-made postcards. They won’t mail as a standard postcard though instead, they fall into the jumbo postcard size category. These homemade postcards typically require two stamps.

Do postcard mailers work?

Direct mail marketing in the modern business world (one that now revolves around the internet, more than it does physical brick and mortar business, in many ways) is actually still quite effective. It is possible that direct mail advertising may have a stronger effect than it ever has (because so many companies now overlook the method).

Does a postcard need an envelope?

Postcards don’t require an envelope to be mailed. However, for thin and flimsy postcards, or homemade photo postcards, mailing it in an envelope couldn’t hurt. From a business standpoint, it’s better to forgo the envelopes and save time and money for something more necessary and beneficial.

Does a postcard need a return address?

As with most types of “paper” mail in the U.S., a postcard does not need a return address to be mailed. That said, if you want the option of tracking the postcard, or sending via First Class mail, it will indeed need a return address. 

Also, if the postcard is delivered to the wrong address, or the recipient wishes to return it, they won’t be able to do so if a return address isn’t included on the card. 

How do I protect my postcards in the mail?

Postcards may be protected in several ways. The first way to prevent damage to postcards in the mail is by sending a sturdy well-made mail, to begin with. To protect photo postcards and thinner more fragile postcards, consider slipping them into a UV protective sleeve before dropping them in the mail. 

These see-through sleeves help prevent damaged corners and excessive smudges from mail handlers.

How are postcard stamps sold?

Stamps are typically sold by the USPS in sheets of 20 stamps or rolls of 100 stamps. You may purchase stamps at the local post office, or buy them online through the USPS or a trusted retailer such as Amazon. 

Keep in mind, buying your stamps at the local post office in person is always the most affordable.

Commercial Real Estate Postcard template
Direct mail – postcard example

Takeaways: Postcard sizes

Standard postcards include sizes ranging from 3-inches x 4-inches to 4.25-inches x 6-inches and cost just $0.40 cents to mail. Jumbo postcards range from 5-inches x 7-inches to 6-inches x 11-inches and have a mailing rate of $0.55. Extra-large postcards, however, are mailed at Flat rates, starting at $0.58 and costing upwards of a dollar.