What Is the Right Size for Your Direct Mailpiece?

Article - 2 Min. Read

The size of your mailpiece helps determine your costs. In this infographic, take a look at the pros and cons of the most commonly used sizes.

When you’re planning a direct mail campaign, one of your first decisions will be what size mailpiece to use. That decision will affect how much space you have for your message and how much you pay in postage.

Take a look at the three most commonly used sizes for direct mail.

Postcard Requirements

At least 5″ long x 3.5″ wide x 0.007″ thick
No more than 6″ long x 4.25″ x 0.016″ thick

What you should know

Postcards are an inexpensive way to get an immediate message to customers—they don’t even have to open an envelope. First-Class Mail^® postcards are a great value, too. You pay a lower price than for letters and get all of the benefits, such as forwarding and return services, that come with First-Class Mail service.

However, when you send postcards via USPS Marketing Mail™ service (formerly called Standard Mail), there’s no price break. They cost the same as letters.

Letter Requirements

At least 5″ long x 3.5″ wide x 0.007″ thick
No more than 11.5″ long x 6.125″ wide x 0.25″ thick

What you should know

If you use a standard No. 10 envelope, your piece is clearly a letter. But if you decide to create your own special envelope, or you design a piece to be folded to letter size, be sure to keep the letter dimensions in mind to avoid paying a higher price.

Letters can be mailed at First-Class Mail service or USPS Marketing Mail rates. Unlike postcards, they receive a price break when sent at Marketing Mail rates.

How can I tell whether my piece is 0.007″ thick? As a guide, an index card meets the 0.007″ guideline. But if you’re in doubt, contact your local Business Mail Entry Unit.

Flat Requirements

Have one dimension that is greater than 11.5″ long OR 6.125″ wide OR 0.25″ thick.
Can be no more than 15″ long x 12″ wide x 0.75″ thick.

What you should know

The Postal Service uses the word “flat” to refer to large envelopes, newsletters, and magazines. The maximum size for a flat provides plenty of room to put lots of material in the envelope. But keep in mind that weight usually affects price—the greater the weight, the higher the postage, especially for flats sent as First-Class Mail service.