Postcard sizes for mailing: USPS limits and file dimensions

What are the USPS size limits for postcards?

The USPS Domestic Mail Manual sets minimum and maximum limits for a card to qualify for postcard pricing. It must be at least 3.5 inches high, 5 inches long and 0.007 inch thick, and no more than 4.25 inches high, 6 inches long and 0.016 inch thick. It must be of uniform thickness and made of unfolded, uncreased paper or cardstock, and it cannot weigh more than 3.5 ounces. USPS measures length along the side parallel to the address and height perpendicular to it, so a 4 x 6 card addressed along its 6 inch side is 4 inches high and 6 inches long.

A card smaller than 3.5 x 5 inches is too small to mail on its own. Cards that do not meet the postcard standards must not carry the word "Postcard" on the address side.

What happens when a postcard is larger than 4.25 x 6?

It is still mailable, but it no longer earns postcard prices. A card up to 6.125 inches high, 11.5 inches long and 0.25 inch thick is a letter size piece and pays letter postage. Once any dimension exceeds those limits, the piece becomes a flat, which USPS accepts up to 12 inches high, 15 inches long and 0.75 inch thick. That means popular oversized formats such as 5 x 7, 6 x 9 and 6 x 11 are letters, not flats, while an 8.5 x 11 card is a flat. USPS also requires cards larger than 4.25 x 6 inches to be at least 0.009 inch thick.

Which postcard sizes mail at which price category?

The table covers the postcard sizes in the Voqado configurator plus the common 8.5 x 11 format, with file sizes at 0.125 inch bleed per side and pixel dimensions at 300 pixels per inch.

For machine processing, the category is only part of the picture; the aspect ratio and thickness below decide whether a piece is machinable. To build the files, set up bleed with the dimensions in the second column.

What is the aspect ratio rule for postcards?

Divide the length by the height. USPS standards call for a result between 1.3 and 2.5, inclusive. A 4 x 6 card gives 1.5, a 4.2 x 5.5 card gives about 1.31, a 5 x 7 card gives 1.4, a 6 x 9 card gives 1.5 and a 6 x 11 card gives about 1.83, so all of them pass. Square cards give 1.0 and fail, which means they cannot be processed on automated letter equipment and are charged extra as nonmachinable mail. If you love a square format, budget for that surcharge or send it in an envelope.

How thick does a mailed postcard need to be?

For postcard pricing, a card must be between 0.007 and 0.016 inch thick. USPS notes that an index card is thick enough to meet the minimum. Oversized cards need at least 0.009 inch. Check the stock too: the standard postcard product lists a 0.4 mm thickness, about 0.016 inch and right at the postcard limit, and a 0.6 mm premium thickness, about 0.024 inch, which mails at letter prices even at 4 x 6. Thin cards bend and tear in processing equipment, so heavier cardstock is safer for any card that travels without an envelope. Attachments such as stickers or magnets can disqualify a card from postcard pricing or make it nonmailable, so check with USPS before adding them.

What size postcard do you need for EDDM?

Every Door Direct Mail delivers to every address on chosen carrier routes without a mailing list, but EDDM Retail only accepts flat size pieces. Under the USPS Quick Service Guide for EDDM Retail, a piece needs at least one dimension over 10.5 inches long, 6.125 inches high or 0.25 inch thick, and it can weigh no more than 3.3 ounces. That rules out 4 x 6, 5 x 7 and 6 x 9 cards, while a 6 x 11 or 8.5 x 11 card is long enough. Check the design with the Mailpiece Size Checker in the EDDM Online Tool. Each EDDM Retail mailing needs at least 200 pieces and allows up to 5,000 pieces per day per ZIP Code. If you want the printing, addressing format and bundling handled for route mailing, look at direct mail postcards, and use the EDDM print checklist before you submit artwork.

Where do the address and barcode go on a mailed postcard?

The delivery address and postage go on the same side. USPS reserves a barcode clear zone in the lower right corner of that side, 4.75 inches from the right edge and 0.625 inch from the bottom, which must stay free of printing. Place the address above it in type of at least 8 points, keep your message on the left portion of the back, and use a light, plain background behind the address block.

What should you send your mail provider before you design?

Before artwork is final, send your mail provider the finished width and height, stock caliper, quantity, mailing class, address orientation and who will prepare the mailing. Ask them to confirm the accepted template and any changes needed. The same 5 × 7 artwork works as a handout without a mailing layout, but mailing it needs a fresh review of the address area and postal classification.

How do you choose a postcard size for a campaign?

• Mailing to your own list on a tight budget: 4 x 6 or 4.2 x 5.5 at postcard prices.
• Need room for a menu, map or before and after photos: 5 x 7, 6 x 9 or 6 x 11 at letter prices.
• Saturating neighborhoods with EDDM: a card longer than 10.5 inches or taller than 6.125 inches, confirmed in the Mailpiece Size Checker.
• Handing cards out rather than mailing them: any size, including square formats.
• Mailing in envelopes: check the fit with the envelope fit checker before ordering.

If you are deciding between the two most common sizes, compare 4 x 6 versus 5 x 7 for space, postage and handling. For most first campaigns to a house list, standard postcards at 4 x 6 inches are the lowest postage option that still leaves room for an image, a headline and an offer.