EDDM Postcard Sizes and Specs: The Complete USPS Guide

The single most common production problem I see with clients attempting to run EDDM without a printer’s guidance is size. Either the piece is too small (postcard-sized pieces under 6.125 inches tall do not qualify for EDDM), or the design is set up at a common commercial size that falls outside the EDDM-eligible flat range.

The USPS specifications for EDDM are specific and non-negotiable. A piece that doesn’t meet the size, weight, or thickness requirements gets reclassified or rejected at the post office counter — meaning your campaign either doesn’t mail or you pay a significantly higher postage rate than planned.

After 28 years of running EDDM campaigns for Hudson Valley businesses, here is every spec you need to know before going to press.

The EDDM Size Window

EDDM Retail pieces must qualify as flats under USPS definitions. A flat is larger than a letter but smaller than a parcel. The specific size window is:

• Height (shorter dimension): Minimum 6.125 inches, maximum 12 inches
• Length (longer dimension): Minimum 11.5 inches, maximum 15 inches
• Thickness: Maximum 0.75 inches
• Weight: Maximum 3.3 ounces

Pieces that fall below the minimum size — including standard 4x6 or 5x7 postcards — do not qualify for EDDM Retail rates. They are letter-sized and would require a different mail class and permit. Pieces above the maximum size move into parcel territory, with significantly higher postage.

The most important dimension to remember: the minimum EDDM piece is 6.125 inches by 11.5 inches. Everything else follows from that baseline.

The Most Popular EDDM Formats

Within the qualifying EDDM flat window, these are the formats we print most frequently at Cornerstone:

6x9 Inch Postcard

The minimum qualifying size — or close to it — and the most economical. At 6 inches tall and 9 inches wide (note: EDDM requires 11.5 inch minimum length, so true 6x9 postcards do not qualify unless printed landscape with the 9-inch dimension as the height).

To be precise: a standard 6x9 postcard mailed landscape (9” is the height) with a 12” or longer length qualifies. More commonly, clients use 6.5x9 or 6x11 for the minimum qualifying footprint.

6.5x9 Inch

Our most frequently ordered EDDM format for clients looking at cost efficiency. Prints two-up on a standard 13x9 press sheet, keeps paper cost down, and the piece is large enough to carry a strong headline, offer, and visual. All-in cost for 5,000 pieces typically falls between $600 and $800 including postage.

6x11 Inch

A strong format that fits efficiently in the EDDM flat window. The extra length versus width gives it good shelf presence when delivered and stands out in a mail stack. Popular for restaurant menus, home service offers, and seasonal promotions.

8.5x11 Inch

Standard letter-size, but oriented as a flat. This is our most popular size for home service businesses — HVAC, landscaping, roofing — where the extra space allows for a service list, multiple photos or illustrations, and a strong coupon or offer. The larger format demands more attention from the recipient. Cost for 5,000 pieces runs $900–$1,200 all-in.

9x12 Inch

Maximum visual impact at the cost of efficiency. Typically used for real estate listings with large property photos, premium service announcements, or campaigns where standing out in the mailbox is the primary goal. More expensive to print and the additional paper weight needs to stay under 3.3 oz.

8.5x14 Inch

Used when a brochure-style format is needed — a trifold or bifold that opens to reveal more content. Less common for EDDM because the fold adds production cost and complexity, but effective for businesses that want to include detailed service or menu information.

Paper Stock Requirements

EDDM pieces travel through USPS automated sorting equipment and carrier vehicle stacking before delivery. Paper stock needs to be heavy enough to survive this process without curling, bending, or sticking together.

Minimum recommended: 80 lb. gloss text (acceptable but borderline — we don’t recommend it) Standard for most EDDM jobs: 100 lb. gloss cover Premium alternative: 100 lb. matte cover (popular for a more sophisticated feel, slightly less vibrant color) Large format (8.5x11 and above): 100 lb. gloss or matte cover — lighter stock will be rejected by postal acceptance staff for failing the rigidity requirement

Coatings

• Gloss UV coating: Protects the ink, adds vibrancy, industry standard for promotional postcards
• Matte coating: Subdued finish, less glare, works well for service businesses that want a more refined aesthetic
• Aqueous coating (AQ): Water-based, less protective than UV, used for pieces that need to be written on after delivery

The Indicia Clear Zone

Every EDDM piece requires the EDDM Retail indicia in the upper right corner of the address face. This is the postage imprint that identifies the piece as EDDM and includes your printer’s postal permit number.

The bottom 2.125 inches of the address face must remain clear of any design elements, text, or graphics. This is the USPS barcode/delivery area. Design elements placed in this zone will either obscure the USPS-applied barcode or cause the piece to be rejected at acceptance.

The right side of the address panel must also carry the EDDM indicia in the standard USPS-compliant format. Your printer will apply this during production.

Bleed, Safe Zone, and File Setup

For print production, set up your EDDM file with:

• 0.125 inch bleed on all sides (for designs that extend to the edge)
• 0.125 inch safe zone minimum, 0.25 inch preferred for critical text and logos
• Color mode: CMYK (not RGB — RGB files convert to CMYK at print and colors shift)
• Resolution: 300 DPI minimum for images, 600 DPI for line art and text
• File format: Print-ready PDF preferred; InDesign package or native files accepted

Weight: The Hidden Spec Violation

The 3.3 ounce maximum is the spec most clients don’t think to check. For single-layer postcards on standard paper stock, weight is rarely an issue — a 6.5x9 postcard on 100 lb. cover weighs approximately 0.7–0.9 ounces. But larger formats printed on heavier stock with UV coating can approach the limit, and any additional insert or perforation adds weight.

We weigh every job before bundling. If a piece is over 3.3 oz, it either needs to be reclassified (which changes the postage rate significantly) or the paper stock needs to drop to a lighter weight.

Common Size Mistakes That Cause Rejection

After processing thousands of EDDM jobs, these are the size-related errors we catch most frequently:

Standard 4x6 postcard submitted as EDDM. A 4x6 postcard is letter-class mail — it does not qualify for EDDM Retail. EDDM requires the piece to be at minimum 6.125 inches in the shorter dimension and 11.5 inches in the longer dimension. A 4x6 or 5x7 postcard will be rejected at the counter. If your budget only supports a smaller piece, you need targeted mail with presort postage, not EDDM.

Design set up at 6x9 without checking orientation. A 6x9 piece can qualify for EDDM only if the 9-inch dimension is the height (shorter side). But standard 6x9 postcards are typically designed with 6 inches as the height and 9 inches as the width — and 6 inches is below the 6.125-inch EDDM minimum. We recommend 6.5x9 as the minimum safe size to avoid this issue.

Finished size measured before trim. The press sheet is larger than the finished piece. Some designers set up files at the correct dimensions but forget that the trimmed piece loses 0.125 inches on each side to bleed trim. A design set up at exactly 6.125x11.5 with bleed will trim to approximately 5.875x11.25 — which falls below the EDDM minimum. Set your document dimensions to the finished trim size and add bleed outside those dimensions.

Folded pieces that exceed thickness. A tri-fold self-mailer on heavy stock (100 lb. cover, three panels) can approach or exceed the 0.75-inch thickness limit when bundled. We measure individual piece thickness before bundling — a single piece at 0.3 inches means a bundle of 50 is 15 inches tall, which creates handling issues even if individual thickness is compliant.

Choosing the Right Size for Your Campaign

The decision framework is straightforward:

Budget-constrained campaigns → 6.5x9. Lowest print cost, efficient press layout, adequate space for a single offer with one photo and a headline. This is the workhorse format for restaurants, service businesses, and seasonal promotions.

Message-heavy campaigns → 8.5x11. When you need to communicate multiple services, include a menu, show before/after photos, or present a service comparison, the extra space justifies the extra cost. Home services companies and healthcare practices use this size most frequently.

Maximum impact campaigns → 9x12. For grand openings, real estate property showcases, or premium brand announcements where standing out in the mailbox is the primary objective. The cost premium is significant — 30–50% more than 6.5x9 — but the visual impact is undeniable.

Menu or catalog needs → 8.5x14 folded. When the content requires interior pages. A bi-fold 8.5x14 opens to 8.5x28 inches of content — enough for a full restaurant menu, a detailed service catalog, or a multi-property real estate showcase. Production cost is highest due to folding and tabbing requirements.

For Hudson Valley businesses running their first EDDM campaign, we almost always recommend starting with the 6.5x9 or 8.5x11 format. These sizes have the broadest production experience behind them, the most competitive printing pricing, and enough track record in our shop to predict response rates with reasonable confidence.

Let Us Handle the Specs

The simplest approach to EDDM specs is to have your printer set up the templates and verify the finished files before production. At Cornerstone, we provide EDDM-compliant templates for every common size, verify bleed and safe zone on every submitted file, weigh every job before bundling, and confirm USPS acceptance before considering the job complete.

To discuss your EDDM piece size and get a quote, call (845) 255-5722 or request a quote. We’ll confirm specs the same day.