How small an envelope can you mail

The United States Postal Service (USPS) has specific guidelines for the minimum size and weight of an envelope that can be mailed. Here are the details:

Minimum Size:

• The minimum size for a letter-sized envelope is 3.5 inches (8.9 cm) long, 6.125 inches (15.6 cm) high, and 0.007 inch (0.18 mm) thick.
• The minimum size for a large envelope is 6.125 inches (15.6 cm) long, 11.5 inches (29.2 cm) high, and 0.25 inch (6.4 mm) thick.

Minimum Weight:

• The minimum weight for a letter-sized envelope is 1 ounce (28.35 grams).
• The minimum weight for a large envelope is 2 ounces (57.15 grams).

Other Requirements:

• The envelope must be sealed and have a valid postage stamp or permit.
• The envelope must have a return address and the recipient's address printed or written legibly.
• The envelope must not be torn, mutilated, or damaged in a way that prevents it from being delivered.

Special Considerations:

• If you're mailing a very small envelope, you may need to use a special type of postage, such as a "letter rate" stamp, which is designed for small, lightweight items.
• If you're mailing a very large or heavy envelope, you may need to use a special type of postage, such as a "flat rate" envelope or a "package" rate, which is designed for larger or heavier items.

It's always a good idea to check with your local post office or the USPS website for specific guidelines and requirements for mailing small envelopes.