Postcard Printing for Direct Mail: Sizes, Paper, and What Actually Works

The postcard is the workhorse of direct mail. No envelope to open, immediate visibility, lower production cost per piece than a letter package, and strong response rates when the offer is right and the design is executed well. In 28 years of running printing services for Hudson Valley businesses, the postcard format remains the starting point for more campaigns than anything else we produce.

But “postcard” covers a wide range — from a 4x6 First-Class mailing to a 9x12 EDDM flat. The right choice depends on your audience, mail class, offer, and budget. Here is what you need to know before selecting a format.

Postcard Sizes and the Mail Classes They Qualify For

The USPS defines mail class eligibility by dimensions and weight. Choosing the wrong size can mean paying First-Class postage rates on what you intended as bulk Marketing Mail — or disqualifying the piece from EDDM.

4x6 Inch — First-Class Postcard Rate

A 4x6 postcard (technically: 3.5”–4.25” tall, 5”–6” long) qualifies for First-Class postcard postage — currently $0.38 per piece versus $0.68+ for a First-Class letter. No permit required. The 4x6 is the simplest, lowest-barrier direct mail format.

Best for: Small test mailings to your house file, appointment reminders, thank-you cards, announcement postcards. Not appropriate for acquisition campaigns because the piece is too small to carry a compelling offer alongside your business information.

5.5x8.5 Inch — Marketing Mail Letter Rate

The most popular format for Marketing Mail (bulk) campaigns. At $0.21–$0.28 per piece with a presort permit, the per-piece postage savings over First-Class are substantial at volume.

Best for: Targeted acquisition campaigns, new mover mailers, seasonal offers, any campaign where you want a reasonable-sized piece at the lowest bulk postage rate. This is the size we recommend most often for new clients running their first targeted direct mail campaign.

6x9 Inch — Marketing Mail Flat or EDDM

At 6 inches tall, the piece upgrades from a letter to a flat. This changes the postage rate — flats cost slightly more than letters in Marketing Mail. The visual impact of the larger format often more than compensates.

Best for: Home service businesses, real estate, healthcare. The extra space allows a stronger visual, more copy, and a larger headline. A 6x9 or 6.5x9 postcard on 100 lb. gloss is also the most common EDDM format.

9x12 Inch — Maximum Flat Size

The largest common postcard format before moving into self-mailer or brochure territory. Postage is the same flat rate as a 6x9, but printing cost is significantly higher.

Best for: High-impact introductory mailers, real estate listings where large property photos matter, premium product announcements. Not appropriate as a regular campaign format due to printing cost.

Paper Stock: What Holds Up Through USPS Handling

Direct mail postcards travel through automated USPS sorting equipment — conveyor belts, rollers, optical readers — before reaching a carrier’s vehicle and ultimately the mailbox. The piece needs to be stiff enough to survive this process without curling, bending, or sticking.

100 lb. gloss cover: The industry standard for direct mail postcards. Stiff, holds ink color well, UV coating option adds protection and vibrancy. This is what we print on for the majority of our campaigns.

100 lb. matte cover: Same weight and stiffness as gloss, but with a subdued, non-glossy finish. Popular for healthcare, professional services, and businesses that want a more sophisticated aesthetic. Colors print slightly less vibrantly than on gloss stock.

14 pt. card stock: Equivalent to approximately 90–100 lb. cover. Used for premium business card-style postcards where extra stiffness is a brand signal.

80 lb. gloss text: Acceptable for 4x6 First-Class postcards where the piece is light enough to stay under the 1 oz First-Class letter threshold. Not recommended for larger formats — the reduced stiffness leads to bending and reader perception of lower quality.

Coatings

UV coating: Applied to the print surface after printing. Protects ink from scuffing and moisture, adds visible shine, makes colors pop. Standard for glossy promotional postcards.

Aqueous (AQ) coating: Water-based, less protective than UV. Used when the piece needs to be written on (address side of self-mailers) or for pieces that will be scanned (some campaigns use QR-code-heavy designs where high gloss causes glare issues).

No coating: Used on matte pieces or when the uncoated look is intentional. Less protection — fine for short-duration campaigns, not ideal for pieces that sit in a mailbox in rain or humidity.

Quantities and Pricing

Postcard printing is significantly price-efficient at volume. Here are real pricing ranges from our shop in New Paltz for standard 5.5x8.5 and 6x9 formats on 100 lb. gloss cover with UV coating, two-sided full color:

Quantity	5.5x8.5 Price	6x9 Price
500	$120–$150	$145–$185
1,000	$155–$195	$185–$230
2,500	$220–$270	$270–$330
5,000	$300–$380	$360–$440
10,000	$460–$560	$540–$660

These prices are for print only — postage and mailing services are quoted separately. Add the mailing services quote to get your all-in campaign cost.

What Actually Makes Postcards Work

The most common reason postcard campaigns underperform is not the paper stock or the size — it’s the offer. A postcard with a generic message (“We provide great home services in your area!”) will consistently underperform a postcard with a specific, time-limited offer (“Free HVAC tune-up inspection — expires March 31. Call (845) 555-1234.”).

The postcard is small enough that the reader decides in 3 seconds whether to keep it or throw it away. Every design decision should serve that 3-second window: large headline with the offer, one compelling visual, and a clear call to action with a phone number or URL.

For campaign design alongside printing, see our graphic design for direct mail guide. For postage and mailing, see mailing services.

Postcard Design: The 3-Second Rule

Every element of a direct mail postcard must serve the 3-second window — the time between the recipient pulling the piece from the mailbox and deciding to keep it or throw it away. These design principles consistently produce higher response rates:

Front of card (non-address side): One dominant image, one headline, one offer. The headline should communicate the value proposition in 7 words or fewer. The image should show the result the customer wants — a finished landscaping project, a renovated kitchen, a happy family at a restaurant table. Do not show your logo as the dominant element; show the outcome your customer is buying.

Back of card (address side): Reinforcing detail, secondary offer terms, your business name, address, phone number, and URL. If the postcard is for targeted direct mail, the address panel takes up approximately one-third of the back — design the remaining two-thirds as supporting content. If the postcard is for EDDM, the address area is simpler (no individual addresses) but the indicia and barcode clear zone still require reserved space.

Color and contrast: Use high-contrast color combinations for the headline and CTA. Dark text on a light background is more readable than reverse text (light on dark) for body copy. Reserve reverse text for short headlines or single-line callouts where readability is less of a concern.

Tracking mechanism: Every postcard should include a tracking element — a unique promo code, a dedicated phone number, or a campaign-specific landing page URL. Without tracking, you cannot measure the campaign’s return and cannot make informed decisions about future drops.

Multi-Drop Campaigns: Why One Mailing Is Not Enough

The most common mistake businesses make with postcard direct mail is treating it as a one-time experiment. A single mailing to a list produces a baseline response rate — typically 0.5–1% for a cold list, 2–5% for a warm house file. That single data point is not enough to evaluate the channel.

The businesses that see the strongest results from postcard mail at Cornerstone run multi-drop campaigns — the same list (or carrier routes, for EDDM) receives a postcard 3–4 times over a 3–6 month period. Each subsequent drop builds on the recognition created by the previous one. By the third or fourth mailing, the recipient recognizes your business name, remembers the previous offer, and is significantly more likely to respond.

The economics of multi-drop campaigns also improve: design is a one-time cost (with minor updates for each drop), printing cost per piece drops when multiple runs are booked simultaneously, and response rates climb with repetition. A campaign that costs $3,500 for a single 5,000-piece drop might cost $9,000 for three drops — but produce four times the cumulative response of the single mailing.

Postcard Printing and Mailing: The One-Shop Advantage

At Cornerstone, postcard campaigns move from design approval to press to the mail department without leaving our facility in New Paltz. This matters for three reasons:

Timeline control. When print and mail are in the same building, there is no shipping gap. Pieces come off the press, move to addressing and sorting, and go to USPS — all within the same production schedule. A campaign that needs to arrive by a specific date can be managed to the day.

Quality continuity. The same team that prints the piece also prepares it for mailing. If a press issue affects a small batch of pieces, the mail team catches it before those pieces go into the mail stream. Split-vendor workflows create handoff gaps where quality issues pass unnoticed.

Single point of accountability. One vendor, one invoice, one contact. If something goes wrong — a print defect, a mailing list error, a missed deadline — there is one party responsible for resolution. When print and mail are at different vendors, finger-pointing between them costs you time.

To get a quote for postcard printing — with or without mailing services — call (845) 255-5722 or request a quote.