Types of mail
Whether you use Retail or Bulk mailing, the Postal Service recognizes 4 types of mail; postcards, letters, large envelopes and parcels. The Postal Service classifies your mail piece by its dimensions.
In addition to what we usually think of as a booklet, many newsletters are considered Letter-sized Booklets - Please review postal service requirements or this type of mail.
Postcards

|
minimum |
maximum |
length* |
5 inches |
6 inches |
height |
3 1/2 inches |
4 1/2 inches |
thickness |
0.007 inches |
0.016 inches |
*length is the dimension parallel to the address.
|
Back to top
Letters (including oversized postcards)

|
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 |
weight |
|
3.3 ounces |
*length is the dimension parallel to the address. |
Back to top
Flats (Large Envelope) - are not necessarily in envelopes and have special requirements; they must be:
- Flexible
- Rectangular with 4 square corners
- Uniformly thick
- For enveloped pieces all of the delivery address must be on one half (right or left) of the envelope.
- For non-enveloped pieces the delivery address must be at least 8 point in size and placed entirely in the top half of the mail piece (see graphic below)

|
minimum* |
maximum |
length |
11 1/2 inches |
15 inches |
height |
6 1/8 inches |
12 inches |
thickness |
1/4 inch |
3/4 inch |
weight |
|
16 ounces |
* large envelopes exceed at least one of these dimensions and length is the longest dimension. |

Back to top
Parcels - a few things to note:
- length + girth cannot exceed 108 inches
- length = the longest side of the parcel
- girth = measurement around the thickest part of the parcel
- Parcels may incur surcharges if they are oversized; please review Postal Standards.

|
minimum |
maximum |
length |
6 inches |
34 inches |
height |
3 inches |
17 inches |
thickness |
1/4 inch |
17 inches |
weight |
|
16 ounces |
Back to top
Letter-sized Booklets - if not placed in an envelope, many newsletters are considered booklets; the Post Office has special requirements for booklets:
- Booklets are comprised of sheets or pages
- If stapled, booklets must be fastened by at least 2 staples in the fold
- Booklets are open on 3 sides before sealing, similar in design to a book
- In general, booklets must be nearly uniformly thick
- Large booklets may be folded to letter-size for mailing if the final piece remains uniform in thickness
- The bound edge of the booklet must be on the bottom or on the right hand side (as you read the address label)
- Booklets must be tabbed using three, non-perforated 1 1/2" tabs as closures (see Design Chart below)
- Large or heavy booklets must be closed with three, non-perforated 2 inch tabs (see Desgn Chart below)
- Tabs may overhang the edge of the booklet by 1/16th of an inch
- Weight of cover stock has been increased (see Design Chart below)
- Please note...Spiral bound booklets are not uniformly thick and don't qualify for the lowest mailing rate - you can still save, just not as much
|
minimum |
maximum |
length |
5 inches |
10 1/2 inches |
height |
3 1/2 inches |
6 inches |
thickness* |
.009 inch |
.25 inches |
weight |
|
3 ounces** |
* thickness is measured at the spine
** booklets weighing over 3 ounces must be placed in sealed envelopes, and mail at large envelope rates |
Design Chart - in September 2009, new requirements for tab positioning and cover weight go into effect.
This chart will help you correctly position tabs and determine the appropriate weight for cover paper
As you look at the address label,
And the spine or fold is... |
And the length is… |
The cover stock must be at least… |
You must seal the piece with… |
And place the tabs in these locations… |
On the bottom (longer) edge |
5” to 9” long
Over 9” up to 10.5” long |
|
Three 1.5” non- perforated tabs |
Two tabs on right edge; one tab on left edge. Position lower right tab 0.5 inch from the bottom edge. Position upper tabs 1 inch from the top edge. |
Final fold on the bottom (longer) edge, with the folded spine on the right or left (shorter) edge |
5” to 10.5” long
|
22 pound |
Three 1.5” non- perforated tabs |
For a larger, folded booklet:
Two tabs on right edge; one tab on left edge. Position lower right tab 0.5 inch from the bottom edge. Position upper tabs 1 inch from the top edge. |
Spine on the right (shorter) edge |
5” to 9” long
Over 9”, up to 10.5” long |
|
Three 1.5” non- perforated tabs |
Two tabs on top edge; one tab on left edge. Position top tabs 1 inch from left and right edge. Position left tab in the middle. |
Spine on bottom (longer) edge, non-perforated inner flap on top (upper) edge |
5” to 9.5” long |
44 pound |
Continuous
glue line or glue spots |
Perfect bound or saddle stitched with a
continuous glue line along flap preferred, minimum 1inch glue spots acceptable if placed within ¾ inch of right and left edges. |
Back to top
|