How big can a post card be?

Answer by  MathWiz (1408)

To use a postcard stamp, your card needs to be at least 5' long X 3 1/2 and no larger than 6' long X 4 1/4' high.

Answer by  Erynn (1651)

Post cards can be any size that fits within the letter category of posting, but I believe they have a reduced postage charge (they do in the UK, I don't know about the USA) if they're approximately photograph size, which is around the normal. It all depends what you want to pay and what you want to send.

Answer by  demoniu (8)

If you want to make your own postcard, it doesn't matter how big it is. It's how special it is. You can make a very small one which has some pretty patterns, or make something really big like a map then draw what means to you and the one you want to give the card