Introduction
Your EDDM mailpiece can look perfect and still get bounced back. Why? The dimensions don't clear USPS thresholds.
Every Door Direct Mail runs on a strict dimensional window set by the U.S. Postal Service. Miss the minimum size, exceed the maximum thickness, or overshoot the weight limit, and your piece loses EDDM eligibility entirely. USPS may reclassify it as a parcel and charge parcel-rate postage.
Acceptance depends on more than length and width. Thickness, folded dimensions, weight, and address-side layout all decide whether USPS takes the piece.
This guide covers current USPS size limits, the most common EDDM formats, paper and design considerations, and the validation steps that catch problems before they become expensive mistakes.
Key Takeaways
- Confirm EDDM pieces meet current USPS size, thickness, and weight limits before ordering.
- Common 4x6 or 5x7 postcards typically don't qualify for EDDM because they fall below minimum size thresholds.
- Formats like 6.25x9, 6.5x9, and 9x12 each offer different design space and cost trade-offs.
- USPS acceptance hinges on folded size, paper thickness, and address-side markings, not flat dimensions alone.
- A full-service print and mail partner catches size and marking issues before pieces reach the post office.
What EDDM Size Represents
EDDM size refers to the finished physical dimensions and characteristics of a mailpiece — the length, height, thickness, and weight USPS uses to classify it as an eligible flat. Measure the completed piece, not the digital design file.
Length is always the longest side. Height is the dimension perpendicular to it. This holds true regardless of whether your design reads as portrait or landscape — USPS doesn't care how the piece looks, only how it measures.
Size is a postal eligibility requirement, not a creative preference. A beautifully designed 5x7 postcard can lose EDDM eligibility simply because it's too small. No amount of clever copywriting fixes a dimensional problem.
What Shapes EDDM Size in Production
Several real-world factors shape which size actually makes sense for a given campaign:
- Message complexity — one offer needs less space than a multi-service menu or coupon set
- Printer standards — sizes that match existing equipment and templates usually cost less than custom dimensions
- Stock and finishing — coatings, folds, and trim tolerances can change final thickness and weight versus the digital file
- Campaign scale — route quantity, bundling, and handling all interact with the size you choose
A printer's "standard" size is not the same as USPS's legal minimum — standard formats exist for production efficiency, not because USPS requires them.
Range of EDDM Size and USPS Requirements
USPS eligibility for EDDM-Retail hinges on two things at once: clearing a minimum qualifying threshold and staying under maximum dimensional, thickness, and weight limits.
Per current USPS Quick Service Guide specifications, here's the reference window:
| Requirement | Minimum | Maximum |
|---|---|---|
| Length | 5 inches | 15 inches |
| Height | 3.5 inches | 12 inches |
| Thickness | 0.007 inch | 0.75 inch |
| Weight | — | 3.3 ounces per piece |
Qualifying rules that sit alongside those limits:
- At least one dimension must exceed 10.5 inches (length path) or 6.125 inches (height path)
- Thickness must clear the 0.25 inch qualifying threshold when that path applies
- Finished pieces still cannot exceed the maximums above
These figures apply to EDDM-Retail. Larger BMEU mailings, which require an active USPS Marketing Mail permit, follow different weight allowances. Always verify current numbers with USPS before finalizing a design — postal rules do change.
Nominal and Commonly Used EDDM Sizes
6.25x9 inches is the default entry-level EDDM size for many print runs. It stays affordable, clears USPS thresholds comfortably, and leaves room for a headline, offer, and call to action without wasted space.
Other common formats worth comparing:
- 6.5x9 — slightly more room than 6.25x9, similar cost profile
- 6.5x12 — better for menus, multiple coupons, or service lists
- 8.5x11 — a familiar "letter" footprint that works well for detailed offers
- 9x12 — near the top of the practical range, strong for maps or multi-panel layouts
- 12x15 — the largest commonly produced size, matching USPS's maximum length/height envelope
These labels are printer conventions tied to common press setups, not USPS rules. Eligibility still depends on measuring the finished piece against the table above.
Allowable Tolerance and Boundary Limits
Designing exactly at a minimum threshold leaves no room for trimming variance. Build in a practical margin so the finished piece still clears USPS limits after cut and fold.
Folded pieces need special attention here. A brochure that measures fine flat can become noncompliant once folded — the fold itself changes the effective dimensions and thickness. USPS's own bulletin guidance uses an 8.5x11 sheet folded in half as an example of a piece that may no longer qualify as flat-sized once folded.
Safe Operating Margin
Before committing to a large print run, validate a physical sample:
- Measure finished trim size with a calibrated tool on the final folded piece
- Check thickness with a gauge, especially on heavier stock or coatings
- Weigh a finished sample to confirm it stays at or under 3.3 ounces
- Confirm the piece still flexes within USPS flat-flexibility expectations
A familiar standard size won't automatically outperform a custom one, but it does cut production risk and speeds artwork setup.
Key Technical Properties of an EDDM Mailpiece
Dimensional compliance is only part of the equation. Size works alongside material properties and postal-marking requirements, and missing any one of them can still sink a mailing.
Thickness and Weight
USPS caps EDDM-Retail thickness at 0.75 inch and weight at 3.3 ounces per piece, with a minimum thickness of 0.007 inch.
Paper terms add confusion because pounds, points, and GSM are not directly interchangeable:
- Points measure physical thickness (one point equals 0.001 inch)
- Pounds reflect a grade-specific basis weight
- GSM measures grams per square meter
Domtar's paper terms glossary is a solid reference for how these units relate. Converting between them without checking manufacturer specs is risky.
Heavier cardstock feels more premium and holds up better in transit, but it also pushes closer to the weight ceiling faster than lighter cover stock. Board stock adds rigidity but can create folding and coating complications.
Shape, Flexibility, and Finish
Flat-size mailpieces must be rectangular, with finished corners limited to a 0.125-inch radius. They also must pass a flexibility test: a standard flat extended halfway needs to bend at least 1 inch vertically.
Rounded corners, heavy lamination, perforations, and unusual coatings can all affect whether a piece still qualifies as "flexible" under USPS standards. Review any specialty finish with your printer before committing to a production run.
Address-Side Layout and Mailability
Every EDDM piece needs the simplified "Postal Customer" addressing along with the EDDM Retail Indicia, placed above and to the right of the address block. USPS guidance recommends leaving 1/8 inch of clear space around the top and right edges for this markup, and bundles need a facing slip listing ZIP code, route number, and piece count.
A large canvas doesn't excuse a cluttered address side. Keep the marketing message and the postal-processing area visually separate.
Coupling With Campaign Goals
Match format to message density:
- Smaller qualifying sizes suit concise single offers and simple calls to action
- Mid-size formats (6.5x9, 8.5x11) balance a headline, offer, and secondary detail
- Larger formats (9x12 and up) fit menus, service lists, maps, or multiple coupons
A restaurant running a single discount doesn't need the same canvas as a home-service company listing five offerings. There's no universal best size, only the size that fits your message and budget.
How EDDM Size Is Specified, Measured, and Validated
Size is both a design spec and a physical quality-control checkpoint. Verify it before printing, before bundling, and again before postal drop-off.
Specification and Documentation
A solid project brief documents:
- Finished size and folded size (if applicable)
- Stock, coating, and ink coverage
- Quantity, route selection, and entry method
Our quote process, for example, captures flat size, finished size, quantity, page count, ink type, and bleed requirements up front. Those details prevent guesswork once a job hits the press.
Rated paper specifications and measured values on the finished piece aren't always identical. Trimming, coating, and ink coverage can shift the final result slightly.
Measurement and Verification Methods
Three checks matter, and they're not interchangeable:
- Digital file check: confirms artwork dimensions but says nothing about finished weight or thickness
- Printed proof review: shows color and layout, useful but still not a finished-weight indicator
- Production sample measurement: the only check that confirms trim size, thickness, weight, and flexibility on the actual output
A preflight checklist should cover:
- Finished and folded dimensions
- Thickness, weight, and rectangular shape
- Corner radius, bleed, and safe zones
- Indicia placement and generic address text
Our proofing process shows clients what to expect once a job comes off press, so sizing or bleed issues are caught before a full run is committed.
In-House Review Before Postal Entry
At Digital XPress, we support EDDM projects with in-house creative development, print production on equipment like our HP T250 web press, and in-house mailing preparation backed by an on-site USPS Postal Clerk. That combination reviews each mailpiece for size and postal compliance before it enters the mail stream, not after a rejection notice arrives. Clients get one coordinated workflow instead of juggling separate design, print, and mail vendors.
Implications of Operating Outside the Recommended Range
A noncompliant piece doesn't just get quietly fixed. It can get rejected outright, require costly rework, lose EDDM eligibility, or get reclassified at parcel pricing.
Always confirm the specific consequence with USPS or your mailing provider before assuming the worst or best case.
Common mistakes worth avoiding:
- Confusing standard postcard sizes (like 4x6) with EDDM-qualifying dimensions
- Measuring an unfolded sheet instead of the finished, folded piece
- Treating nominal paper weight as proof of actual thickness
- Ignoring finished weight until after printing is complete
- Designing the postal indicia and address area as an afterthought
Bigger isn't automatically better. The right format depends on message density, audience, route strategy, and budget—not just how much space you can fill.
USPS rules and postage categories shift periodically, so confirm current requirements before every campaign rather than reusing last year's template.
Conclusion
EDDM size determines whether your mailing gets delivered at all. Treat finished dimensions as a hard requirement, not a late-stage design detail.
Choosing a compliant finished size, appropriate stock, and a realistic design margin protects mailability while still supporting your campaign's message and budget.
Before committing to a large production run, validate a physical proof. If you're unsure where a format lands relative to USPS thresholds, confirm with a qualified print and mail provider before printing thousands of pieces that might not qualify.
Frequently Asked Questions
What postcard sizes are allowed for Every Door Direct Mail (EDDM)?
USPS requires EDDM-Retail pieces to meet set minimum and maximum dimensions—typically larger than everyday postcards and closer to oversized postcard or flat formats. Always confirm current thresholds with USPS before finalizing artwork.
What are the standard sizes for direct mail postcards?
Standard direct-mail postcards, such as 4" × 6" or 5" × 7", often fall short of EDDM minimum size requirements. Base size selection on your mailing class, campaign goals, and confirmed USPS eligibility.
What are the differences between direct mail and Every Door Direct Mail (EDDM)?
Traditional direct mail targets specific names and addresses from a purchased or owned list, while EDDM saturates entire carrier routes using simplified "Postal Customer" addressing. EDDM also carries its own size, weight, and preparation requirements distinct from addressed mail.
What are common mistakes when using Every Door Direct Mail (EDDM)?
The most frequent errors include undersized mailpieces, measuring unfolded instead of folded dimensions, exceeding thickness or weight limits, and missing indicia or generic addressing. Poor artwork margins and incomplete postal preparation also cause rejections.
Are Every Door Direct Mail (EDDM) postcards worth it?
EDDM works well for broad local awareness and route-based saturation campaigns, particularly for businesses targeting an entire neighborhood. Value depends on audience fit, offer quality, route selection, and how well the campaign gets measured afterward.
