Mail Services
Mailpiece Dimensions
The Postal Service classifies the shape of your mailpiece by its dimensions.
| Postcards Dimensions | |||
|---|---|---|---|
 |
minimum | maximum | |
| length | 5 inches | 6 inches | |
| height | 3-1/2 inches | 4-1/4 inches | |
| Diagrams not to scale. Maximum thickness 0.016 inch | |||
| Letters Dimensions | |||
 |
minimum | maximum | |
| length | 5 inches | 11-1/2 inches | |
| height | 3-1/2 inches | 6-1/8 inches | |
| thickness | 0.007 inches | 1/4 inch | |
| maximum thickness 1/4 inch | |||
| Flats Dimensions | |||
 |
minimum* | maximum | |
| length | 11-1/2 inches | 15 inches | |
| height | 6-1/8 inches | 12 inches | |
| thickness | 1/4 inch | 3/4 inch | |
| *Flats exceed at least one of these dimensions. | |||
