Mail Piece Design

Priority Mail International

The dimensions for Priority Mail International in an envelope or package are:

  Minimum Maximum
Length
(parallel to the address)
5½ inches 24 inches
Height
(perpendicular to the address)
3½ inches  
Thickness 0.007 inches  
Length and Girth Combined
(girth equals twice the width
plus twice the depth)
  79 inches*
Weight None Flat-rate envelope - 4 pounds
Flat-rate box - 20 pounds
All other packaging - Varies by country

*

S everal countries have a higher maximum length and girth combined.  For a circular package, the maximum girth, as measured around the diameter, is 64 inches. 


First-Class Mail International

Post Cards

The dimensions to qualify for the post card rate are:

  Minimum Maximum
Length
(parallel to the address)
5½ inches 6 inches
Height
(perpendicular to the address)
3½ inches 4¼ inches
Thickness 0.007 inches 0.016 inches
Aspect Ratio
(length divided by height)
1.3 2.5

Cards larger than 4¾ x 9¼ inches must be enclosed in an envelope.

Letters, Flats and Packages

The dimensions for envelopes or packages are:

  Minimum Maximum
Length
(parallel to the address)
5½ inches 24 inches
Height
(perpendicular to the address)
3½ inches  
Thickness 0.007 inches  
Length Plus Height Plus Depth   36 inches
Weight None 4 pounds

 

The dimensions for a tube are:

  Minimum Maximum
Length
(parallel to the address)
4 inches 36 inches
Length Plus Twice the Diameter 6¾ inches 42 inches
Weight None Varies by
destination country


Nonstandard Surcharge

If your letter, flat or package meets one or more of the following characteristics, a $0.17 nonmachineable surcharge is added to the postage:

  • The length exceeds 11½ inches or the height exceeds 6 1/8 inches or the thickness exceeds ¼ inch.
  • Has an aspect ratio (length divided by height) of less than 1.3 or more than 2.5
  • Is polybagged, polywrapped or enclosed in any plastic material
  • Has clasps, strings, button or similar closure devices
  • Contains items such pens, pencils or loose keys or coins that cause the thickness of the mail piece to be uneven
  • Is too rigid (does not bend easily when subjected to a transport belt tension of 40 pounds around an 11 inch diameter turn)
  • For pieces more than 4¼ inches high or 6 inches long, the thickness is less than 0.009 inch
  • Has a delivery address parallel to the shorter dimension of the mail piece
  • For folded self-mailers, the folded edge is perpendicular to the address, regardless of the use of tabs, wafer seals or other fasteners
  • Is a folded self-mailers with the folded edge perpendicular to the address unless the final fold is on the right side (leading edge) and the left edge (trailing edge) and other edges opens are secured with at least one tab or glue line.
  • Is a booklet type piece with the bound edge (spine) along the shorter dimension of the piece or at the top.