Choosing the right postcard size goes beyond just being a design decision; it also affects postage costs, readability and how your message performs. Choosing the wrong option can increase mailing costs, limit design clarity or reduce how likely people are to notice and respond to your message. This postcard size guide breaks down standard postcard sizes, including the dimensions in inches, millimeters and pixels, and how to make the right decision for your marketing goals.
- The standard postcard size in the U.S. is 4″ x 6″, which qualifies for USPS postcard postage.
- Postcard sizes are measured in inches, millimeters and pixels, depending on print and digital use.
- Larger postcard dimensions improve visibility but increase printing and mailing costs.
- Bleed, trim and safe areas affect how your design prints across different sizes.
- Choosing the right postcard size helps avoid redesigns and unnecessary postage costs.
- Global postcard standards differ; always verify local postal requirements.
What does postcard size refer to?
Postcard size refers to the finished width and height of a printed postcard after trimming. Like poster sizes, postcard sizes are typically listed in inches or millimeters for print, and pixels for digital artwork. Standard sizes are designed to meet mailing regulations while leaving room for readable text and strong visuals.
What size is a postcard?
If you were to ask us, “What’s the size of a postcard?” we wouldn’t have a quick answer. That’s because the dimensions of postcards can vary based on the vibe you’re aiming for, the image you intend to use and the purpose behind creating the postcard.
Ultimately, there are no rigid boundaries here. Postcards come in all shapes and sizes, and you can feel free to choose the postcard size that appeals to you.
However, some postcard dimensions are more popular than others. The standard postcard size in the U.S. is 4″ x 6″. These fit in most envelopes and mailboxes, making them an ideal choice for multiple uses.
| Postcard size | Inches | Approx. millimeters | Approx. pixels (300 dpi) | Common use |
| Standard | 4″ x 6″ | 102 x 152 mm | 1247 x 1847 px | Direct mail, promos |
| A6 | 4.1″ x 5.8″ | 104 x 148 mm | 1228 x 1748 px | Events, invites |
| Medium | 5″ x 7″ | 127 x 178 mm | 1500 x 2100 px | Marketing campaigns |
| Jumbo | 6″ x 11″ | 153 x 280 mm | 1805 x 3305 px | High-impact mailers |
Why postcard sizes perform differently in real-world campaigns
Postcard sizes aren’t arbitrary. Smaller formats are designed for quick scanning and cost efficiency, which makes them effective for reminders and coupons. Larger postcards increase visibility at arm’s length, allow more design flexibility and are more likely to stand out in crowded mailboxes, which can improve response rates for promotions and brand announcements.
Why is 4″ x 6″ the standard postcard size for businesses?
In the U.S., postcards must meet USPS size requirements to qualify for postcard postage rates. A standard postcard must be rectangular, measure at least 3.5″ x 5″ and no more than 4.25″ x 6″, with a thickness between 0.007″ and 0.016″. Anything larger is mailed as a letter, which increases postage costs.
Design and printing specifications by size
Understanding technical requirements ensures your postcards print correctly.
Bleed, trim and safe area dimensions:
- Bleed area: 0.125″ (⅛″) on all sides beyond the trim size
- Safe area: Keep text and logos at least 0.125″ inside the trim edge
- For A6 postcards: VistaPrint recommends 151 x 108 mm full bleed
Paper stock suggestions:
- Glossy stock: Best for photo-heavy designs and vibrant colors
- Matte finish: Ideal for text-heavy postcards and professional tone
- Cotton paper: Premium option for elegant, textured feel
- Plastic/synthetic: Weather-resistant for outdoor use or durability
How size affects readability and layout: Smaller postcards (4″ x 6″) require concise messaging with larger fonts (minimum 10-12pt body text). Larger sizes (5.5″ x 8.5″ and up) allow breathing room for multiple design elements, smaller text and complex layouts without feeling cramped.
Postcard size standards around the world
Postcard size standards vary by region. In the U.S., mailing rules are governed by USPS. The USPS-approved size for standard postcard postage is 3.5″ x 5″ minimum up to 4.25″ x 6″ maximum. In the UK and EU, A-series sizes like A6 (104 x 148 mm) are commonly used. In Australia, A6 and DL formats are popular for print marketing materials and event promotions. Always check local mailing regulations before printing large volumes.
These measurements are applicable to both our standard postcard size (4″ x 6″) and other postcard dimensions available on the Vista site. To learn more information, you can always check the details on our postcard product page. Check out our guide to crop marks to better understand safety, bleed and trim lines.
Postcard sizes available on the Vista website
If you’re not planning to send your postcards through the mail, there’s no reason you can’t consider different postcard dimensions.
With the help of Vista services, you have the option to print postcards in the following sizes:
| Size | Best for |
| 4” x 4” | Brand awareness handouts, in-store promos, social-first designs |
| 4″ x 6″ | Standard mailings, coupons, reminders |
| 4.2″ x 5.5″ | Compact promotions, loyalty cards |
| 5″ x 7″ | Event invites, announcements |
| 5.5″ x 8.5″ | Product showcases, detailed promos |
| 6″ x 9″ | High-impact campaigns |
| 6″ x 11″ | Jumbo mailers, real estate |
Unconventional postcard sizes and modern design trends
Beyond standard rectangles, unconventional postcard formats can help your marketing stand out:
Square postcards create visual interest and work well on social media when repurposed digitally. They break the mold of traditional mailers and demand attention in a stack of rectangular mail.
Jumbo postcards (6″ x 11″ or larger) offer maximum impact for product launches, open houses or high-value promotions. While they cost more to print and mail, their size commands attention and allows for dramatic imagery.
Panoramic formats work beautifully for landscape photography, real estate listings or showcasing wide products. These elongated dimensions create a cinematic feel that standard sizes can’t achieve.
Digital postcards are gaining popularity as social media companion pieces. Design your physical postcard at dimensions that translate well to Instagram (1080 x 1080 px for square) or Facebook (1200 x 630 px). This lets you extend your campaign across both print and digital channels with consistent branding.
When choosing unconventional sizes, remember they may not qualify for standard postage rates, so factor increased mailing costs into your budget.
More postcard design tips
Now that you’ve got your postcard dimensions down pat, here are some other things to consider when designing.
Keep your design simple. Postcards are relatively small, so a lot of complicated information can overwhelm people when reading. Identify the top few things you want a customer to know, and then focus on those points. Including a strong call to action – visiting your website, following you on social, leaving a review – gives people a way to learn more once they’ve become interested in what you have to say.
Stand out with photography or a logo. Odds are good that your postcard will be competing for attention with other promotional pieces – in a letterbox, on a notice board or at markets. Bold colors, a high-quality image or your logo can help your postcard get noticed.
Think dual-purpose. Make your postcard work twice as hard for you. Use the reverse side for appointment reminders, loyalty stamps or as a blank canvas to showcase something about your business. Check out our guide on how to write a postcard for more information.
Elevate with a special finish or paper. Cotton paper has a natural texture that’s best for elegant, crisp designs. Our glossy stock really lets images pop, and indestructible plastic is a great option for outdoor or heavy-duty use.
Stick to clean, simple postcard fonts and avoid overly decorative styles that can make your postcard hard to read.
Create a consistent look by incorporating your branding elements, such as fonts, logos and colors, into your postcards. A cohesive design ensures your postcards align with your other marketing materials, helping to establish a recognizable and professional brand identity.
Choosing the right postcard size for your marketing goal
Mass direct mail: 4″ x 6″ for lower postage costs
For high-volume campaigns, standard 4″ x 6″ postcards keep costs low while meeting USPS postcard postage requirements. This size is perfect for announcements, coupons and reminders where budget efficiency matters more than visual impact.
Event invitations: A6 or 5″ x 7″ for a premium feel
Event invitations benefit from slightly larger sizes like A6 (4.1″ x 5.8″) or 5″ x 7″, which convey quality and importance. These sizes provide enough space for event details and imagery while still fitting standard envelopes.
In-store promos: Medium sizes that balance cost and visibility
Medium postcards like 5″ x 7″ or 5.5″ x 8.5″ work well for in-store handouts and counter displays. They’re large enough to catch attention but small enough to keep printing costs reasonable for local campaigns.
Package inserts: Smaller sizes that fit easily into boxes with things like brochures
For package inserts, stick to 4″ x 6″ or smaller. These fit easily alongside products and other materials like brochures without adding significant shipping weight or bulk.
Postcard marketing ideas for all postcard sizes
Now that you’ve designed your perfect postcard, it’s time to put it to work. Here are our top postcard marketing ideas:
- Voucher cards. Add a stamp or punch-hole to your design and reward regulars for their loyalty.
- Appointment reminders. Hand out a postcard after every appointment to encourage customers to use your services again.
- Offers and promos. Have a sale or special deal? Spread the word with a compact postcard. Pass out on the street or pop into local mailboxes.
- Event announcements. Planning a special do or grand opening? Make your postcard a promo vehicle and an invite.
- Package inserts. A postcard in every box and parcel is a great way to reinforce your brand identity. Ask customers to leave a review, encourage them to follow you on social media or tell your brand story.
FAQ about postcard sizes
What is the most popular postcard size?
The most popular postcard size in the U.S. is 4″ x 6″. It is compact, fits easily into mailboxes and meets USPS requirements for postcard postage rates
Which postcard size qualifies for standard postage?
In the U.S., postcards measuring between 3.5″ x 5″ and 4.25″ x 6″ with thickness between 0.007″ and 0.016″ qualify for USPS postcard postage rates. Anything larger is classified and charged as a letter.
What size postcard is best for marketing?
The best postcard size for marketing depends on your goal. Standard 4″ x 6″ postcards are cost-effective and versatile, while larger sizes like 5.5″ x 8.5″ offer more space and higher visibility.
What postcard size is best for marketing campaigns that need attention?
Larger postcard sizes can help your message stand out in crowded mailboxes. Oversized formats give you more room for imagery, headlines and calls to action, but they may increase printing and postage costs.
Can I use custom postcard sizes?
Yes, you can use custom postcard sizes to suit your design and campaign needs. Custom dimensions can help your postcards stand out, especially for events, promotions or premium brand messaging.
What is the minimum size for a postcard?
The minimum postcard size approved by USPS is 3.5″ x 5″. Anything smaller does not qualify for postcard postage rates and will be mailed as a letter.
