EDDM® sizes and requirements: which postcards qualify
Every Door Direct Mail® only takes "flats", pieces bigger than a regular postcard or letter. If your card is even a quarter inch too small, the Post Office won't accept it at EDDM® prices. Here are the USPS size rules, the sizes that work, and the ones that don't.
The short answer
An EDDM® piece has to be longer than 10.5 inches, taller than 6.125 inches, or thicker than 0.25 inch. Meeting any one of the three is enough. It also can't be bigger than 15 × 12 inches or thicker than 0.75 inch, and for EDDM® Retail it can weigh no more than 3.3 ounces.
All the EDDM® size and weight rules
| Must be a flat | Longer than 10.5 in, taller than 6.125 in, or thicker than 0.25 in (any one) |
| Largest size | 15 in long, 12 in high, 0.75 in thick |
| Smallest size | 5 in long, 3.5 in high, 0.007 in thick (a flat must also pass the rule above) |
| Weight | Up to 3.3 oz for EDDM® Retail; heavier pieces can go as a commercial mailing, priced by weight |
| Quantity | At least 200 pieces per mailing; EDDM® Retail allows up to 5,000 per ZIP Code per day |
Source: USPS Domestic Mail Manual section 140 and the USPS Quick Service Guide for EDDM® Retail flats, current as of October 2026.
Popular EDDM® postcard sizes
These are our three most popular EDDM® sizes. All three pass the size rule and weigh far less than 3.3 ounces.
| Size | Why it qualifies | Good for | 2,500 cards, mailed |
|---|---|---|---|
| 6.25 × 9 in | 6.25 in tall, just over 6.125 | A simple offer at the lowest price | $1,108 |
| 6.25 × 11 in | Over the limit both ways | A photo plus an offer | $1,239 |
| 8.5 × 11 in (recommended) | Over the limit both ways | Standing out in the mailbox, menus, before-and-after photos | $1,458 |
Prices include printing, USPS postage and mailing. See how much EDDM® costs for every quantity from 1,000 to 10,000. Other sizes also qualify, such as long 4.25 × 14 menus (longer than 10.5 inches). If you have a size in mind, ask us.
Sizes that don't qualify
- 4 × 6 and 5 × 7 postcards. Regular postcard sizes, too small for EDDM®.
- 5.5 × 8.5 (half sheet). Short on both limits.
- 6 × 9. The most common mistake. It looks big, but at 6 inches tall and 9 inches long it misses both limits. Making it 6.25 × 9 fixes it.
- Letter-size envelopes. A #10 envelope is a letter, not a flat, so it goes as regular addressed mail.
Smaller cards still work well as addressed mail sent to a list. For that we recommend a 6 × 11 postcard. You can buy a targeted mailing list by area, home value, age and more.
Why a bigger card is usually the better buy
USPS charges the same EDDM® postage, about $0.26 a piece in 2026, for every eligible size up to 3.3 ounces. So going from 6.25 × 9 to 8.5 × 11 only adds printing cost: at 2,500 cards the whole mailing goes from $1,108 to $1,458. In return you get the biggest piece in the mailbox and room for a photo, a clear offer and your phone number in large type.
Requirements beyond size
- Indicia. Each card needs the EDDM® postage indicia printed in the top right corner of the address side. See what the EDDM® indicia says.
- Address line. In place of a name and address, the card says "Postal Customer" (or "Local Postal Customer" for EDDM® Retail).
- Bundling. Cards go to the Post Office in bundles of 50 to 100 with a facing slip on each. See how EDDM® bundling works.
- Attachments. Stickers and similar extras are allowed if every card has the same one and it's firmly attached. First-Class Mail enclosures are not allowed.
Need an EDDM® template?
We can send you a print-ready template in any size that qualifies for EDDM®, with the indicia and address area already marked so your design stays clear of them. Or start from one of our postcard designs and we'll size it for EDDM® for you. See what goes on an EDDM® postcard.
Frequently asked questions
What size does a postcard have to be for EDDM®?
It has to be a flat: longer than 10.5 inches, taller than 6.125 inches, or thicker than 0.25 inch. It can be no bigger than 15 × 12 inches and 0.75 inch thick, and for EDDM® Retail it must weigh 3.3 ounces or less.
Is a 6 × 9 postcard EDDM® eligible?
No. A 6 × 9 card is 9 inches long and 6 inches tall, so it falls just short of both limits. A 6.25 × 9 card is the smallest common size that qualifies, because 6.25 inches is taller than 6.125.
Can I send a 4 × 6 postcard with EDDM®?
No. A 4 × 6 card is a regular postcard size and is too small for EDDM®. It can be mailed to a list of addresses instead.
What is the most popular EDDM® postcard size?
6.25 × 11 and 8.5 × 11 inches are the most common. We recommend 8.5 × 11: it's the biggest card in the mailbox and costs the same to mail.
Does a bigger EDDM® postcard cost more postage?
No. EDDM® postage is the same for every eligible size up to 3.3 ounces, about $0.26 a piece in 2026. A larger card only costs more to print.