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A Guide to Postcard Sizes

Drithligh enjoys researching the usage and functionality of postcards.

Read on to learn all there is to know about postcards!

Read on to learn all there is to know about postcards!

This article will cover the following:

  • The standard postcard size
  • Other postcard size options to fit your needs (you'll find a table that compares different sizes and USPS's requirements)
  • USPS postcard requirements
  • How to send a postcard through first-class mail
  • How to determine the correct paper weight for your postcard

What Is the Standard Postcard Size?

The standard postcard size is about 4" x 6", which is a typical, fairly rectangular-shaped postcard. Also, it fits within the U.S. Post Office's regulations to receive the special postcard postage rate.

However, many postcard makers use slightly different sizes for a variety of reasons. Some people prefer how a slightly more boxy postcard looks. Some printing services just want to maximize the number of postcards they can print on a large sheet of paper.

Whatever the reason, you'll find that the standard postcard size will often vary by as much as a 1/2 inch from a standard 4" x 6" postcard.

Here are some popular postcard printers' sizes:

  • Hallmark: 4.3" x 6"
  • 4" x 6"
  • 4" x 6"
  • 4.25" x 5.6"
Postcard Size Comparison

Postcard Size Comparison

What Are Other Postcard Size Options?

Beyond the standard postcard size, there are many options available that serve different design requirements.

A postcard can be any size between 3.5" x 5" and 6.125" x 11.5." As long as your postcard is thick enough (but less than 1/4 inch thick) and fits within the above dimensions, it will be able to be processed by the Post Office machines.

If you want your postcard to stand out from the rest, or if you just have a lot to say, you don't have to be restricted to the standard size. Instead, you can make a bigger postcard! (I know my politicians love to send out the giant postcards right before an election . . . )

Some of the typical larger sizes available for postcards are:

  • 4" x 9" (long and narrow—like a sheet of paper folded in half the long way)
  • 5.5" x 8" (just a big postcard—like a sheet of paper folded in half the short way)
  • 6" x 11" (pretty much as big as you can get)

If you're designing your own postcard, make sure to find out which size options your printer offers before you start designing. You don't want to waste time making the perfect postcard if you can't print it.

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Also, remember that these larger postcards will cost you more to mail. And if you try to mail something larger than 6-1/8" x 11-1/2," you're going to pay a lot more!

Why Should You Care About Postcard Size Regulations?

To save money, of course!

When making postcards, whether for business or personal purposes, you should know that USPS has size regulations on postcards. Basically, the Post Office has a range (small to large) that a postcard has to fit within.

Postcard Size Range:

  • Min: 3.5" x 5"
  • Max: 6.125" x 11.5"

Any piece of mail that is too small or too large cannot flow through the processing machines, so the Post Office won't deliver it. Or they'll charge a heck of a lot to do it!

Send Postcards Through Standard Mail

If you intend to mail your postcards through standard mail, then your postcard can be any size within reason. However, the cost is based on size, shape, and weight. A smaller, standard size postcard will cost less.

Standard mail is only for business (you can't send personal messages) and must follow these guidelines:

  • The entire piece must be pre-printed (no handwriting).
  • You must mail at least 200 pieces at a time.
  • It does not offer forwarding and return service.

What Are First-class Postcard Regulations?

First-class mail has a fairly narrow range for the dimensions that can be sent using the postcard rate postage. Anything beyond that will cost you letter rate postage.

First-Class Postcard Size Restrictions:

  • Minimum: 3.5" x 5" (0.007 in. thick)
  • Maximum: 4.25" x 6" (0.016 in. thick)

Additionally, odd-shaped postcards (square or really thin and long) will cost even more to mail than just large, rectangular postcards.

So if you want to get really creative with your postcard design and don't have a lot of postcards to mail, then you may not care about standard postcard regulations. The cost to mail each postcard will just be more.

The difference between each rate bracket is actually quite a lot (relatively):

  • First-class postcard rate: $0.28
  • First-class letter rate: $0.44 (57% more expensive)
  • Odd shaped rate: $0.64 (129% more expensive)

So, if you have about 100 postcards to mail out (say a wedding "Save the Date" postcard), then mailing at postcard rate will save you $16. But, if you want to get fancy with your cards and make them perfectly square, you'll end up paying $64 instead of the basic $28 just for the stamps.

If you need to send out 1,000 postcards to customers, then the First-class rate will cost you $160 more than the postcard rate.

USPS Postcard Requirements for Special Postcard RatePostcard Size OptionsFirst-Class Postcard Size Restrictions

Minimum size: 3.5" x 5

4" x 6" (standard size)

Minimum: 3.5" x 5" (0.007 in. thick)

Maximum size: 6.125" x 11.5"

4" x 9" (long and narrow—like a sheet of paper folded in half the long way)

Maximum: 4.25" by 6" (0.016 in. thick)


5.5" x 8" (just a big postcard—like a sheet of paper folded in half the short way)


6" x 11" (pretty much as big as you can get)


What's the Right Paper Weight for a Postcard?

If you are ordering postcards from a printing service, then you most likely do not need to worry about the thickness of the paper the printer is using. They (probably) know what they're doing.

However, if you want to print your own postcards, then you need to make sure that you buy the right "weight" of paper. USPS says that paper that is about as thick as an index card is thick enough. It's likely that any paper labeled "cardstock" will work, but let's get technical.

In the U.S., bulk amounts of paper are often sold with the "thickness" labeled as "weight" and will be measured in lbs. (or #). Technically, this isn't perfectly correct, but to explain this exactly would get into paper/printing specifics that aren't important for this article. The thing to remember is that you want to buy paper with the right "weight" to be a postcard.

  • 39# paper = about .0072 inches thick per sheet
  • 87# paper = about .015 inches thick per sheet

Remember, these thicknesses are approximate. If you buy a really fluffy sort of paper, it might have a lighter weight but a larger thickness (meaning it's not dense). But you'd have to get really weird paper for this to be a problem.

Generally speaking, any paperweight between 40 lbs. and 85 lbs. should be postcard thickness. If you're worried, aim for 60 lb. paper.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


Dale Anderson from The High Seas on September 13, 2018:

This was cool, thansks for sharing this with us all.

Jacqui on October 23, 2014:

This is such a great help! Thank you.

printer on September 25, 2012:

whoever wrote this article knows very little - there are a lot of mistakes

Cristini on June 14, 2012:

I love postcards!

So much emotion can be put out there on one little piece of mint-smelling card! Ah, life has many pleasures.

Jeff_McRitchie on June 06, 2011:

This is a great Hub. Who knew there were so many things to know about postcards?

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