The 10-second answer
Mailing to a list (past customers, a targeted audience) and want the lowest print cost? A 6x9 or smaller postcard is perfect. Blanketing a whole neighborhood with EDDM? You need a bigger card — 6.5x9 or 9x12 — because EDDM has a minimum size. Pick the size after you pick how you're mailing.
The EDDM size rule (read this first)
This trips people up, so here it is plainly: to qualify for USPS Every Door Direct Mail and its discounted postage, your mailpiece must be a "flat" — meaning it has to exceed 6.125" in height OR 11.5" in length (a standard postcard is too small). So:
- 6x9 postcard → great for targeted/first-class mail, but does not qualify for EDDM.
- 6.5x9 postcard → just clears the 6.125" height — EDDM eligible.
- 9x12 (and 8.5x11, 6x12) → comfortably EDDM eligible and hard to miss in the mailbox.
Bottom line: if EDDM is your plan, don't order a 6x9 — go 6.5x9 or larger. If you're mailing to a list, size is all about budget and impact.
Popular postcard sizes compared
| Size | EDDM eligible? | Best for |
|---|---|---|
| 4x6 | No | Lowest-cost targeted mail, reminders |
| 5x7 | No | Targeted mail with a bit more room |
| 6x9 | No | Targeted mail, strong standard size |
| 6.5x9 | Yes | Smallest EDDM-eligible saturation card |
| 8.5x11 | Yes | Big EDDM piece, lots of room |
| 9x12 | Yes | Maximum-impact EDDM, hard to ignore |
Bigger isn't always better — unless you're doing EDDM, where bigger is required. Match the size to the mailing method first, then to your message.
6x9 & standard sizes: targeted mail
If you have a mailing list, smaller cards (4x6 up to 6x9) keep your print and postage costs low while still delivering a clear offer. 6x9 is a sweet spot: big enough for a real headline and image, small enough to stay affordable at volume. These mail as First-Class or Standard to the exact addresses you choose.
6.5x9, 9x12 & up: EDDM saturation
For EDDM, you're blanketing routes with no list — and the big card is the advantage. A 9x12 lands like a small poster in the mailbox, giving you room for a bold offer and a strong call to action. 6.5x9 is the budget-friendly EDDM entry size; 9x12 is maximum impact. New to EDDM? Start with our EDDM vs targeted guide and the EDDM campaign page.
How to choose your size
Every i Can Print That order includes a free professional file check, so your postcard is sized and set up right for the mailing method you choose.
Right size, right mailbox.
Pick your postcard size, see your price instantly, and it ships to your door — or we help you mail it.
Order Postcards âš¡ Start an EDDM CampaignFrequently asked questions
What size postcard qualifies for EDDM?
To qualify for USPS Every Door Direct Mail and its discounted postage, the mailpiece must exceed 6.125 inches in height or 11.5 inches in length. Common EDDM-eligible sizes include 6.5x9, 8.5x11, and 9x12. A standard 6x9 postcard does not qualify.
Can I use a 6x9 postcard for EDDM?
No. A 6x9 postcard is too small for EDDM because it doesn't exceed 6.125 inches in height or 11.5 inches in length. Use 6.5x9 or larger for EDDM; 6x9 works well for targeted mail to a list.
What is the best postcard size for direct mail to a list?
For targeted mail to a list, 4x6 through 6x9 postcards keep print and postage costs low while still delivering a clear offer. 6x9 is a popular sweet spot with room for a headline and image.
What is the biggest postcard size for EDDM?
9x12 is a popular maximum-impact EDDM size — it lands like a small poster in the mailbox with room for a bold offer. 8.5x11 is another large EDDM-eligible option.
Does a bigger postcard get better response?
A bigger postcard stands out more in the mailbox, which can lift response, but it also costs more. Match the size to your mailing method and budget: bigger is required for EDDM, while targeted list mailings can succeed with smaller, lower-cost cards.