2nd class mail size

In the United States, the size requirements for 2nd Class Mail are as follows:

Length: The length of a 2nd Class Mail piece must be no more than 11.5 inches (29.2 cm).

Width: The width of a 2nd Class Mail piece must be no more than 6.125 inches (15.6 cm).

Thickness: The thickness of a 2nd Class Mail piece must be no more than 0.25 inches (6.4 mm).

Maximum Weight: The maximum weight for a 2nd Class Mail piece is 3.5 ounces (99 grams).

Size Examples:

• A standard #10 envelope (business-sized) is a good example of a 2nd Class Mail piece. It is typically 6.125 inches wide, 3.5 inches high, and 0.25 inches thick.
• A standard letter-sized piece of paper (8.5 x 11 inches) would not be eligible for 2nd Class Mail because it exceeds the maximum length and width requirements.

Keep in mind that these size requirements are subject to change, so it's always a good idea to check with the United States Postal Service (USPS) for the most up-to-date information.