What is the smallest card you can mail

According to the United States Postal Service (USPS), the smallest card that can be mailed is a standard postcard, which measures 3.5 inches by 5 inches (8.9 cm by 12.7 cm). This is the minimum size required for a postcard to be considered a "postcard" and to be eligible for the reduced postcard rate.

However, if you're looking to send a smaller item, you can consider sending a "letter" instead of a postcard. A letter can be as small as 3.5 inches by 4.5 inches (8.9 cm by 11.4 cm), but it must have a minimum thickness of 0.007 inches (0.18 mm) to qualify for letter rates.

Keep in mind that even smaller items, such as business cards or greeting cards, can be mailed, but they may not qualify for the same rates as postcards or letters. In these cases, you may need to use a larger envelope or pay a higher rate.

Here are some general guidelines for mailing small items:

Remember to check with your local post office or the USPS website for specific guidelines and rates for mailing small items.