Letter Design
Letter Size USPS Parameter:
- Not more than 11-1/2 inches long, or more than 6-1/8 inches high, or more than 1/4-inch thick
- Not more than 3.5 ounces (First-Class Mail letter-size piece over 3.5 ounces pay flat-size prices)
- Rectangular, with four square corner and parallel opposite sides, and an aspect ratio (length divided by height) of more than 1.3 and less than 2.5
- Minimum: 3-1/2 inches high, 5 inches long, and either 0.007 inch thick if not more than 4-1/4 inches high and 6 inches long; or 0.009 inch thick if more than 4-1/4 inches of high or 6 inches long, or both