What Size Are Postcards? Standard Dimensions Explained

The standard postcard size is 4" x 6". It is the format most people picture, and it is the one USPS treats as a standard mailer, which earns the lowest postage rate. It is compact, easy to design, and fits neatly in a mailbox without folding. For a high-volume direct mail campaign on a budget, this is your go-to. But 4" x 6" is not the only option, so here is every common postcard dimension.

4.25" x 5.5", the compact card. This size matches a standard A2 envelope opening, so it is popular for personal correspondence, RSVP cards, and small event invitations. The smaller footprint keeps costs low and works well when your message is short. Think appointment reminders, thank-you notes, or save-the-dates. Because it is slightly smaller than the standard card, it reads more like a note from a friend than an ad, which helps it get read instead of tossed.

4" x 6", the standard. This is the workhorse. It qualifies for USPS First-Class Mail postcard rates, which keeps your per-piece cost as low as possible. You get room for a strong headline, a single image, and a clear call to action on the front, plus contact details and a short message on the back. Real estate agents use it for just-listed mailers, restaurants use it for seasonal menu promos, and nonprofits use it for donation appeals. If you are building other pieces for the same campaign, our how to make flyers guide covers the companion format.

5" x 7", the sweet spot. Need more room than 4" x 6" without jumping to a large-format piece? The 5" x 7" postcard is the middle ground, giving you roughly 40% more printable area than the standard size. That means bigger images, more copy, or both. It is a favorite for event invitations, product launches, and photo-heavy designs, and it still qualifies for standard letter-rate postage when mailed without an envelope, though it costs more than the 4" x 6" rate.

5.5" x 8.5", the half-page powerhouse. Exactly half of a standard letter-size sheet, this size gives you serious design real estate. It is large enough for a small map, a coupon, detailed product info, or a mini menu, and it stands out in the mailbox because it is noticeably bigger than what most people receive. Direct mail marketers reach for it when they want the impact of a flyer with the simplicity of a postcard. Pairing it with a folded piece? Our how to fold a brochure guide covers the companion.

6" x 9", maximum impact. The largest common postcard size dominates a stack of mail. You can fit multiple images, longer copy, tear-off coupons, or a perforated business card section. It is popular for grand openings, major sales events, and political campaigns. The trade-off is higher postage, since it mails at the letter rate rather than the postcard rate, and higher printing cost per unit. When you need maximum visibility, though, 6" x 9" delivers.

Getting your file dimensions right is the difference between a clean print and a card with awkward white edges. Every postcard needs bleed, the extra image area beyond the trim line that gets cut off during production. Standard bleed is 0.125" (one-eighth inch) on each side.

Document sizes with bleed. For a 4" x 6" postcard, set your document to 4.25" x 6.25". For 5" x 7", build the file at 5.25" x 7.25". For 5.5" x 8.5", that is 5.75" x 8.75". And for 6" x 9", your document needs to be 6.25" x 9.25". Keep all important text and logos at least 0.125" inside the trim line so nothing gets clipped, set your resolution to 300 DPI, and work in CMYK for accurate color.

Design considerations by size. Smaller postcards (4" x 6" and 4.25" x 5.5") look best with a single focal image and minimal text, so do not cram too much in. Larger sizes (5.5" x 8.5" and 6" x 9") can carry more complex layouts, but they still need a clear visual hierarchy: one dominant element, supporting details, and a clear call to action. If you are coordinating other formats, our how to make envelopes guide helps you match sizes, and how to clean rubber stamps keeps your return-address stamp printing sharp.

Size and paper stock work together. A flimsy 6" x 9" postcard feels cheap, while a rigid 4" x 6" card feels premium. Here is how to match them.

14pt cardstock is the standard for most postcards. It is sturdy enough to survive the mail without bending and thick enough to feel like a real card rather than a flyer, roughly the weight of a cereal-box panel but stiffer. 16pt cardstock adds noticeable heft, about the thickness of a credit card, which suits 5" x 7" and larger sizes where you want the piece to feel solid. It is a great match for invitations and premium brand mail.

32pt ultra-thick stock is a statement, roughly three times the thickness of a standard business card. At that weight even a 4" x 6" postcard feels like a luxury item, so it is ideal for VIP invitations, high-end brand promos, or any time you want someone to pause. 4OVER4.COM carries all of these weights across every postcard size, plus specialty options like kraft, linen, and pearl finishes.

Now that you know what size are postcards and which dimensions fit your project, it is time to pick a product. 4OVER4.COM prints standard postcards in every size covered here, from 4" x 6" up to 6" x 9", plus direct mail postcards that arrive ready for your mailing list. Want something that stops people mid-sort? 3D lenticular postcards add motion and depth that a flat card cannot.

If you would rather start from a print-ready layout, grab a free blank sized with bleed and safe zones already built in, like the 3D lenticular postcard template or a banner stand template for the display side of your campaign. Every stock and size ships with the same crisp color and fast turnaround, so your mailer looks the way you designed it.