Postcard Sizes: 4x6, 5x7, 6x9, Bleed and USPS Rules

What Size Postcard Mails at the USPS Postcard Rate?

A piece mails at the USPS postcard rate when it is rectangular, at least 3.5 x 5 inches, no more than 4.25 x 6 inches, and between 0.007 and 0.016 inch thick. Miss any one of those four and it does not qualify, whatever you call it.

Letter rate. Anything over the postcard maximum still mails as a letter as long as it stays rectangular and inside 6.125 x 11.5 inches and 0.25 inch thick. A 6 x 9 card is a letter. So is a 5 x 7.

Flat rate. Past 6.125 inches tall or 11.5 inches long the piece becomes a flat, which costs more but gives you the whole 6.5 x 9 or 8.5 x 11 canvas.

Two details catch people out. Square cards, and rounded corners past a certain radius, can draw a nonmachinable surcharge. And thickness is a real limit, not a formality: at 0.016 inch, the 16pt cardstock we print on sits right at the top of the postcard range, which is exactly where you want it for a card that has to survive a mail sort. Postal rules and prices change, so confirm them with USPS before a large mailing, especially near a threshold.

What Is Bleed on a Postcard?

Bleed is the 0.125 inch band of artwork that runs past the trim line and gets cut away, which is 3 mm on all four sides. It turns a 4 x 6 card into a 4.25 x 6.25 inch file, and it exists because paper and blades both move a little.

Cards are not trimmed one at a time. They print many up on a large sheet, the sheets are stacked, and the stack goes through the cutter. That is why the cut is accurate rather than perfect, and why a background that stops exactly at 4 x 6 can come back with a white hairline down one edge. Push the background out into the bleed and the same shift cuts artwork instead of paper.

How Do You Lay Out the Address Side?

The address side adds a constraint no other printed piece has. Reserve the right side of the address panel for the mailing address and the indicia or stamp, and leave the bottom 0.625 inch free of artwork so the Postal Service can print a barcode there.

Keep the background light behind the address block. A dark photo under an address is the most common reason a mailer gets rejected or surcharged, because a scanner has to read printed characters off it at speed. Design that side as a layout with a hole in it, not a full bleed image with text floated on top.

The left third of the address side is yours, and it is the part most people waste. A short reminder of the offer, the deadline and a map or a service list all fit there without touching the address panel.

Which Postcard Size Should I Use?

4 x 6 is the default, and the only one that mails at the postcard rate. Use it for reminders, appointment cards, seasonal offers and anything where volume is high and the message is one line.

5 x 7 is the upgrade that still feels personal. It stands out in a stack of 4 x 6 cards and holds a photograph worth looking at. It mails as a letter.

6 x 9 is the attention size. Nearly twice the face of a 4 x 6, it does not get lost in a handful of mail, and it has room for an offer plus a map or a service list.

5.5 x 8.5 is a half sheet that doubles as a rack insert, a counter handout and a mailer, one file doing two jobs. 6.5 x 9 and 8.5 x 11 mail as flats, so they usually end up as handouts and counter pieces instead.

Plenty of postcards never touch a mailbox at all. They go in a bag at checkout, on a table at a show, or in a welcome packet. When that is the plan, ignore the postage thresholds entirely and pick the size that reads best in a hand, usually 5 x 7 or 6 x 9. Deciding what to print alongside them is its own question, and we worked through it in how to choose marketing materials for any event.

How Many Pixels Is a 4 x 6 Postcard?

A 4 x 6 postcard is 1200 x 1800 pixels at 300 dpi. Pixels only mean something once you attach a resolution, and print resolution on a piece read in a hand is 300 dpi, not the 72 dpi a screen works in.

Here is the trap. A card that looks fine on screen at 72 dpi is only 288 x 432 pixels, roughly a quarter of the detail a press needs in each direction. Printed at card size it goes soft, and small type goes fuzzy first. Vector art, an AI or EPS or layered PDF, has no resolution to run out of and is always the better send. The full ladder is in the size cards at the bottom of this page.

What Do Postcards Cost to Print?

Our custom postcards print on 16pt gloss cardstock, which measures 0.016 inch and sits at the top of the USPS postcard thickness range, double sided at no extra cost, in the three sizes people actually order. A 4 x 6 is $74.89 for 100, $106.99 for 250 and $149.79 for 500. A 5 x 7 is $85.59 for 100, $139.09 for 250 and $203.29 for 500. A 6 x 9 is $106.99 for 100, $171.19 for 250 and $278.19 for 500. Production is about 48 hours once you approve the free digital proof.

For a run longer than 500, or for a matte, writable surface, the same postcard sizes print on our flyer stocks in packs up to 2,500. For a size, stock or finish outside both lists, including 4.25 x 6 cut to the postcard maximum and rounded corners, send the details through custom orders. The rest of the range, including rack cards and brochures, sits on the marketing prints hub.

We print and ship the cards, not the mailing itself, so plan on posting them yourself or handing them to a mail house. Everything is printed in the USA, every order includes a free digital proof, and shipping is a flat $10 ground to any US address.

Mistakes We Catch on Postcard Proofs

Four things account for nearly every postcard file we send back, and three of the four only happen on postcards.

A dark photo running under the address block. This is the one that costs real money, because it passes our press and fails at the post office. If the address side is a full bleed sunset, the address goes on top of it, the scanner struggles, and the piece gets handled by hand or sent back. We flag it on every proof where the address panel is not light and clear.

Artwork in the bottom 0.625 inch of the address side. That strip belongs to the barcode. A logo tucked into the bottom corner looks tidy and is in the way.

A card built one sided when the back is going in the mail anyway. Both faces cost the same on our 16pt stock, so a blank back on a mailer is paid space nobody used. We ask before we print it.

Text sitting on the trim line. A phone number or a deadline that ends an eighth of an inch from the edge reads fine on screen and gets shaved on a real stack. This is the single most common reason we hold a proof on any product, not just cards.

What to Send Us

A print ready PDF at 4.25 x 6.25 inches, CMYK, 300 dpi, fonts outlined or embedded, all text inside the safe zone, and both sides as separate pages. That file goes straight to press.

Here is the short version as a checklist:

• Document built at the bleed size, not the trim size
• 300 dpi, CMYK, photos checked at final size
• Text and logos 0.25 inch inside the trim
• Address side laid out with the right panel and the bottom 0.625 inch clear
• Both sides as separate pages in one print ready PDF, fonts outlined

There is no setup fee. Upload any image or file and we make it print ready: size, bleed, resolution and color. If you have no design at all, Design it for me is +$32.10 and a designer builds the card from scratch with two revisions included.

Our Postcard Size Visual Guide

Four sizes, the same three lines on each, with every number in millimeters, inches and pixels at 300 dpi. Swipe through them and build to the one you need. The wall version of the same message is covered in poster sizes, the vinyl version in banner sizes, and the same bleed and safe zone rules at pocket scale in standard business card size.