There is no single best size — the right one balances impact against postage. Pieces within the USPS postcard size range earn the lowest prices, sizes up to about 6 x 11 inches are priced as letters, and larger pieces are priced as flats. The choice should follow the message, the audience, and the mailing method.
Direct mail format
Postcard Mailing Services
Postcard mailing services cover the full path of a direct mail postcard: choosing a size that fits the intended postal category, designing within the required address and barcode areas, printing, applying any variable data, preparing and addressing the mailing, and depositing it with USPS on the schedule the campaign needs.
Planning a postcard? Talk it throughThe format
When a postcard fits the message
A postcard reads as a short, public message.
A postcard is a strong candidate when recipients should understand the main message without opening an envelope. It can support an announcement, reminder, invitation, service-area message, customer communication, location campaign, or focused acquisition offer.
The available space makes prioritization important. If the campaign needs extensive explanation, several documents, a reply component, or content that should not be displayed openly, another format may be more appropriate.
The format also sets expectations. A postcard reads as a short, public message, which suits an offer or a reminder and works against anything that needs to feel confidential, formal, or detailed. Account notices, regulated communications, and complex propositions generally belong in an envelope.
A postal decision
Postcard sizes and the postal categories behind them
A small change can move the price.
Postcard size is a postal decision before it is a design decision. USPS prices mail by category, and the category is determined by the physical dimensions of the piece, so a small change in size can move a mailing into a different price and a different preparation path.
The lowest postcard prices apply only to pieces within a narrow rectangular size range. Larger pieces are priced as letters, and larger pieces still are priced as flats. Each step up buys more space and more visibility at a higher unit cost, which is a real trade rather than an obvious upgrade.
| Size | Typical postal category | Commonly used for |
|---|---|---|
| 4.25 x 6 in | USPS postcard prices, when within the required size and thickness range | High-volume reminders, short offers, and cost-sensitive campaigns |
| 5 x 7 in | Letter-size prices | A visible step up in space with letter economics |
| 5.5 x 8.5 in | Letter-size prices | Offers needing more copy, a map, or several elements |
| 6 x 9 in | Letter-size prices | A common workhorse size for promotional mail |
| 6 x 11 in | Letter-size prices, at the upper limit of the category | Maximum letter-rate impact |
| 6.5 x 9 in and larger | Flat-size prices | High-impact local mail and larger offers |
| 8.5 x 11 in | Flat-size prices | Detailed offers, menus, and multi-message pieces |
One message
Design for rapid understanding
Read in a few seconds.
A postcard should identify the sender, communicate the main value, show the intended action, and preserve the required addressing and postal areas. The front and back should work as one message rather than as two unrelated advertisements.
Most postcards are read in a few seconds while standing over a recycling bin. The design should survive that: one dominant message, a legible offer, and an action that does not require the reader to search for it.
- A clear audience-relevant headline
- A concise explanation of the message or offer
- Brand and sender identification
- One primary response action
- Readable contact or response information
- Space for addressing and postal requirements
Reserved areas
Reserve the address side correctly
Shared between the campaign and USPS.
The address side of a postcard is shared between the campaign and USPS. The address block, the return address, the postage indicia or stamp area, and the barcode clear zone all have to be present and unobstructed, and design that intrudes on those areas can make a mailing non-compliant after it has already been printed.
Production requirements apply on top of postal ones. Artwork should be built with adequate bleed, safe margins for trimming, and sufficient contrast behind any text, and the address area should sit on a light, uncluttered background so the printed address and barcode remain machine-readable.
- A clear address block sized for the longest expected record
- An unobstructed barcode clear zone
- Reserved space for the indicia, permit, or stamp
- A visible return address
- Adequate bleed and trim margins in the print file
- Light, low-contrast background behind addressing areas
The stock
Paper, coating, and finishing
Stock weight is also a postal limit.
Card stock weight affects durability, perceived quality, and postal thickness limits at the same time. A heavier stock reads as more substantial and survives handling better, but it adds weight and can move a piece out of an intended price category.
Coating changes both appearance and function. A gloss finish makes images look stronger; a matte or uncoated finish is easier to write on, which matters when the campaign asks the recipient to fill something in or when a handwritten element is part of the concept. Specialty finishes can add impact but should be reviewed for cost and for compatibility with addressing and inkjet processes.
Names and codes
Personalize and measure when useful
A scan is an interaction, not a conversion.
Postcards may support names, messages, images, locations, representatives, QR codes, or response URLs when approved data is available.
Campaign-specific response paths can help compare audiences, markets, or versions. A QR-code scan or website visit should be interpreted as an interaction, not automatically as a completed conversion.
The quote
What drives postcard mailing cost
Production and postage respond differently.
A postcard quote combines production and postage, and the two respond to different decisions. Size affects both at once, which is why it is usually the first variable to revisit when a campaign is over budget.
- Size, because it sets the postal category and the press layout
- Quantity, which determines the printing method and unit cost
- Paper weight, coating, and any specialty finishing
- Mail class and presort level
- Variable data — the number of fields, versions, and proofs required
- Data preparation, address hygiene, and suppression work
- Schedule, since compressed timelines narrow production options
Working backward
Plan the schedule backward from the in-home window
Start from the in-home window.
Postcard campaigns are usually tied to a date — an event, a promotion, a season, or an appointment cycle. The schedule should therefore be built backward from the desired in-home window, allowing time for data preparation, proofing, printing, finishing, addressing, postal preparation, entry, and transit.
Mail class matters here as much as production. Transit time varies by class, entry point, and destination, and USPS does not guarantee an exact household delivery date, so a campaign with a hard date should build in margin rather than assume the earliest possible arrival.
FAQs
Questions about postcard mailings
Sizes, personalization, cost, stock and timing.
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