EDDM Postcard Sizes and USPS Rules Explained

EDDM postcards are not like regular mail. The USPS created a specific set of dimensional rules your mailpiece has to meet. Break those rules and you lose access to the program's flat-rate postage, currently around $0.21 per piece. That is a big deal when you are mailing to hundreds or thousands of addresses.

The baseline rule is simple. Your postcard must be either taller than 6.125 inches or longer than 10.5 inches, and it cannot exceed 12 inches by 15 inches. Thickness needs to sit between 0.007 and 0.25 inches. Most standard postcard stocks fall within that range, but it is worth confirming with your printer before you commit to a run.

4OVER4.COM makes this easy. Every Direct Mail Postcard template is pre-built to meet these USPS specifications, so you do not have to guess or measure. Pick a size and start designing.

Just a quarter-inch wider than the standard, the 6.5 x 9 inch size gives you a touch more breathing room. That extra space might not sound like much, but designers appreciate it. It allows slightly larger margins, which makes your layout look cleaner and more professional. It works well for real estate agents showcasing property photos or healthcare providers listing multiple services, and the cost difference from the 6.25 x 9 is minimal, so it is an easy upgrade if your design feels cramped.

The 6.5 x 12 inch format is where things really stand out in a mailbox. Long and narrow, it naturally draws the eye and feels different in the hand. People notice it because it does not look like everything else in the stack. It is a favorite for automotive dealerships, home improvement companies, and fitness studios that need a wide canvas for before-and-after photos, panoramic images, or side-by-side comparisons. For complementary mailers, learn how to make envelopes for your follow-up drop.

Your industry should guide your size selection. Here is how different businesses typically approach it.

• Restaurants and cafes use 6.25 x 9 inches for menu highlights, coupons, and grand opening announcements. Keep it simple and appetizing.
• Real estate agents lean on 6.5 x 12 or 8.5 x 11 inches for property showcases with room for high-quality photos and neighborhood stats.
• Home services like HVAC, plumbing, and roofing use 8.5 x 11 inches to list every service with seasonal offers. Homeowners keep these on the fridge.
• Fitness studios and gyms pair 6.5 x 9 inches with a bold offer like "First Month Free" to drive trial memberships.
• Dental and medical offices favor 8.5 x 7 inches to balance professionalism with space for insurance info and new patient offers.

Want something that really pops? 4OVER4.COM offers 3D Postcards that add a lenticular effect to your EDDM campaign, a guaranteed attention-grabber. And if you want a truly custom outline, explore die-cutting services for a postcard shape that stands out from every rectangle in the stack.

Once you have locked in your EDDM postcard size, your design needs to work within those dimensions. Do not cram every inch with text. White space is your friend, and it directs the reader's eye to what matters, your offer, your phone number, your website.

Keep your headline to seven words or fewer. Use one dominant image, not five small ones. Make your call to action impossible to miss, because "Call Today for 20% Off" in bold type beats a paragraph of copy every time. Guide the eye with the reading path too: on wide cards people scan in a Z-pattern from top-left to bottom-right, so anchor your call to action at the end of that path. On tall narrow formats, stack a bold headline at the top, flow into short bullet points, and land the offer at the bottom.

Bleed is another thing to watch. Always extend background colors and images 0.125 inches past the trim line to prevent white edges after cutting. 4OVER4.COM templates have bleed guides built in, so you will not accidentally lose important content near the edges. For promotional ideas to pair with your drop, check out our guide on how to make custom magnets for items recipients actually keep, and visit our showcase gallery for real design examples.

The most common mistake with Every Door Direct Mail postcard sizes is designing at a non-compliant dimension. If your postcard is 6 x 9 inches instead of 6.25 x 9 it does not qualify for EDDM, and that missing quarter-inch means you pay standard postage rates while your whole budget projection falls apart.

Another frequent error is ignoring the maximum weight limit of 3.3 ounces. Heavier paper stocks on larger formats can push you over, so always confirm your finished weight before printing thousands of pieces. Do not forget the indicia either. EDDM postcards require the specific ECRWSS marking and postage indicia in the address area, and skipping it means the post office rejects your entire mailing. 4OVER4.COM includes proper indicia placement in all EDDM templates, so you never have to format it yourself.

Finally, avoid designing without bleed. A postcard trimmed without bleed shows ugly white borders, an amateur look that hurts your brand's credibility before anyone reads a word of your offer. Set up the file right and every card in the run comes back clean.