
When it comes to postcard postage, a postcard can be any size you want it to be, but the average is the common, photo-sized 6" X 4".
It should be no smaller than 3.5" X 5", and no thicker than 0.007 inches to be able to warrant the standard postcard rate.
As for how large or how thick it can be, the sky's the limit, just be prepared to pay some extra postage!
When preparing to send, the prices you can expect are as follows: domestic will be cheapest, then letter mail, and lastly international.
Postcards with special mailing needs (too thick, oversized) will inflate the rate even further.
Whereas standard and first-class postcard postage are at a fixed rate, international rates tend to fluctuate.
Not only based on the distance of their destination, some post offices separate countries into groups or 'classes,' typically with a certain class being the most expensive locations to send to (usually third world countries or locales where the mailing process is made difficult), counting down to another class containing industrialized, first world nations.
Below is a general price guide for card postage, according to the United States Postal Service (USPS):
| Mailing Service | Price | Weight or Size Restrictions |
|---|---|---|
| Standard Postage | $0.28 | Minimum: 3.5 inches high by 5 inches long, 0.007 inch thick Maximum: 6 inches long by 4.25 inches high by 0.016 inch thick |
| First-Class Mail | $0.44 | Maximum 11 1/2 inches long by 6 1/8 inches high by 1/4 inch thick |
| First-Class International Mail | Group 1: $0.75 Group 2: $0.79 Groups 3-9: $0.98 | Same size constraints as First-Class mail, up to 3.5 ounces |
To work out the exact postage for postcard you need, firstly think about the postcard's destination.
Postcards going internationally will have to go by international mail, no exceptions. Otherwise, sending domestic postcards gives you the freedom to choose your service based on how quickly you would like it to arrive, and whether you'd like it sorted with or apart from regular bulk mail.

Stamped postage
Obviously, check the maximum sizes allowable to see if your postcard will have be sent a certain way, or be charged additional postage.
Oversized postcards, such as those exceeding the maximum criteria for First-Class mail, will have to be charged as a large envelope at double the postage, $0.88 or up to $1.24 if it is going internationally.
Postcards that do fall within mailable constraints but exceed the maximum allowable weight similarly get an escalated rate, the rate climbing up to a possible $0.95 based on the weight.
Postcard stamps can be picked up at the local post office, or in some countries, at their online website.
Stationery stores (such as Hallmark) or convenience stores may also be an alternative. For truly fascinating yet functional postcard postage, check out Stamps.com to make your own customized, fully usable postage.
Have a look here if you're keen to find out a specific postcard stamp price.
If it's postcard stock and supplies you need, we have a page devoted to just that!
Explore our site further for more humbled postcard price guides!