Postal Standards - The Graphic Design: Reference and Specification - page 121

t h i c k n e s s r e q u i r e m e n t s f o r f l at m a i l
( u n i t e d s tat e s )
The USPS also has requirements for the thickness of
cards, envelopes, and flats.

p o s t c a r d pa p e r s t o c k
r e q u i r e m e n t s
In addition to meeting the
thickness and basis weight
standards, the USPS also
has specific recommenda-
tions for postcards

Letter envelopes: Must be 1 ⁄ 4 inch (6.35 mm) or less in
thickness.

Large envelopes or flats: Must be 0.009 inch (0.2286
mm) and no more than 3 ⁄ 4 inch (19.05 mm) in thickness.

• Paper grain: Cards should
be printed so that the paper
grain is oriented parallel to
the long dimension of the
card. Long-grain cards are
less likely to jam automated
postal equipment than cards
with the grain parallel to the
short dimension of the card.

Postcards: Cards measuring 4 1 ⁄ 4 ” × 6” (10.795 mm ×
15.25 mm) or less must be printed on stock that is at
least 0.007 inch (0.1778 mm) or a basis weight of at
least 75#. Postcards larger than 4 1 ⁄ 4 ” × 6” (10.795 mm
× 15.25 mm) must have a thickness of 0.009 inch
(0.2286 mm) or a basis weight of at least 80#.

• Types of paper: Cards can
be printed on 90# index
stock, 120# offset, or 100#
tag. Cover stock is also suit-
able; however, it is advisable
to check with a postal agent
to be certain that the stock
you choose has the proper
weight and rigidity to meet
USPS requirements for
automated mail.

s i z e r e q u i r e m e n t s f o r pac k ag e s
( u n i t e d s tat e s )
Merchandise, catalogs, tubes, and other items not
meeting the description of a letter, postcard, or a flat
are categorized as either bound printed material
(books, catalogs, and other publications) or packages.
Publications must not exceed 15 lb. (6.804 kg) per unit.
Packages must not exceed 70 lb. (31 .752 kg) or measure
more than 130 inches (330.2 mm) in combined length
and distance around the thickest part.

If your package weighs less than 1 lb. (0.46 kg) you can
drop it into a collection box. but, anything over 1 lb.
(0.46 kg) must be handed to your letter carrier or taken
to a post office.