If you've looked into Every Door Direct Mail, you've probably already picked a postcard size. And there's a good chance it doesn't qualify.

EDDM is one of the best deals in direct mail — no mailing list, no permit, and postage under 20 cents per piece. But the USPS has a minimum size requirement that trips up almost everyone.

The rule most people miss

To qualify for EDDM, a mailpiece must be at least 6.125 inches on its shortest side or have a combined length-plus-width of at least 10.5 inches.

Read that number again: 6.125 inches. Not 6. Not "about six." Exactly 6.125.

Why common sizes fail

Here's what happens when you walk into most print shops:

4×6 — Too small in every direction. Not even close.
5×7 — The short side is 5 inches. Fails.
6×9 — This is the one that stings. The short side is 6 inches. EDDM needs 6.125. You're off by an eighth of an inch, and your entire mailing is rejected.

We've seen customers come to us after ordering thousands of 6×9 postcards from an online printer, only to find out at the post office that they can't use them for EDDM. That's an expensive lesson.

The sizes that work

The standard EDDM-compliant sizes are:

6.25×9 — The most popular. Meets the 6.125-inch minimum with a little room to spare.
6.25×11 — More space for your message, still qualifies.
8.5×11 — Letter size, folded or flat. Works if you want maximum real estate.

We print EDDM mailers at 6.25×9 on 14pt or 16pt cardstock, UV-coated on both sides. That's what holds up in a mailbox and looks professional when someone pulls it out.

Why nobody tells you this

Most online printers list 6×9 as an option and don't mention EDDM at all. They're selling you a postcard, not a mailing strategy. By the time you find out the size is wrong, you've already paid.

We tell you before you print. That's part of the job.

The short version

If you're planning an EDDM campaign, start with 6.25×9. It's the smallest size that qualifies, it's cost-effective to print, and it fits in every mailbox. Anything smaller and you're either paying full postage or starting over.

Have questions about setting up an EDDM mailer? We can walk you through the whole process — sizing, design, paper stock, and drop-off at your local post office.