What is a folded self-mailer?
A folded self-mailer (FSM) is a letter-size piece formed by folding a single sheet. It is not enveloped, not bound, and has no staples. It must be sealed closed with tabs (wafer seals) or fugitive glue to qualify for letter-rate postage and to survive USPS high-speed processing without jamming. This sealing requirement is a letter-size rule; a piece folded to flat size is a flat, not an FSM, and does not use these tabs (see Does a sheet folded to a flat size need tabs).
A tri-fold is a sheet folded twice, producing three panels. A bi-fold is folded once, producing two panels. A quarter-fold is folded twice at right angles.
What size can a folded self-mailer be?
Folded (final) dimensions must fall within:
- Length: minimum 5 inches, maximum 10.5 inches
- Height: minimum 3.5 inches, maximum 6 inches
- Aspect ratio (length divided by height): between 1.3 and 2.5
- Thickness: minimum 0.007 inches, or 0.009 inches if the piece exceeds 4.25 inches in height or 6 inches in length
Note: the folded self-mailer maximum (10.5 x 6) is smaller than the general letter maximum (11.5 x 6.125). A piece can be letter-size yet still exceed the folded self-mailer limits, which changes how it must be handled.
Does a sheet folded to a flat size need tabs?
A sheet folded to finished dimensions that exceed letter size (more than 6.125 inches high or more than 11.5 inches long) is a flat, not a folded self-mailer, and it does not need the self-mailer tabs. Flats are prepared under flat standards. Tabbing is a letter-size processing requirement (DMM 201.3.11 through 201.3.17), so the tabbing and sealing rules in this guide apply only to letter-size folded self-mailers.
Worked example: an 11 x 17 sheet folded in half to 8.5 x 11 is 8.5 inches high, which exceeds the 6.125-inch letter height, so it mails as a flat (see What size is a flat) and does not require a tab. Only when a piece is folded down to letter size (for example an 11 x 17 quarter-folded to about 5.5 x 8.5) do the self-mailer tabbing rules in How many tabs does a folded self-mailer need and How many tabs does a quarter-fold need apply.
Does an 8.5 x 11 tri-fold need tabs?
An 8.5 x 11 tri-fold needs tabs. Tri-folded (letter fold), the sheet finishes at about 8.5 x 3.67 inches, which is within the folded self-mailer size limits, so it is a valid folded self-mailer (see How many tabs does a folded self-mailer need for the number of tabs and Which panel does the address go on for panel placement).
How many tabs does a folded self-mailer need?
For basic letter-size bi-fold and tri-fold self-mailers, tabs must be non-perforated and placed on the top edge:
- Up to 1 ounce: two tabs, 1 inch in diameter, on 70 lb book stock
- Over 1 ounce up to 3 ounces: two tabs, 1.5 inch in diameter, on 80 lb stock
Placement options for bi-fold and tri-fold, each tab within 1 inch of the corners:
- Two tabs on the top edge, one near each corner, or
- One tab on the leading edge and one on the trailing edge, each within 1 inch of the top
No tabs are allowed on the bottom edge of a self-mailer.
A sheet folded to a finished size larger than letter is a flat and is not tabbed this way (see Does a sheet folded to a flat size need tabs).
How many tabs does a quarter-fold need?
Quarter-fold pieces need more tabs than bi/tri-folds once they are over 1 ounce:
- Up to 1 ounce: two tabs (same top-edge placement as bi/tri-fold)
- Over 1 ounce up to 3 ounces: three tabs, one on the leading edge and one on the trailing edge within 1 inch of the top, plus a third on the lower leading edge, 0.5 inch from the bottom
Which way should the final fold face?
On a letter-size folded self-mailer, the final fold must be on the bottom; on an oblong piece it must be on the leading (right) edge. It cannot be on the top. Fold a tri-fold from bottom to top so the final folded panel forms the non-address side. These fold rules do not apply to a sheet folded to flat size (see Does a sheet folded to a flat size need tabs).
Which panel does the address go on?
On a letter-size tri-folded self-mailer, the mailing address must be on the middle panel: the center panel, with fold creases on both its top and bottom edges. The final fold creates the non-address side of the piece. Flats place the address in the top half of the piece instead (see Where does the address go on a flat).
What paper weight does a self-mailer need?
- 1 ounce or less: at least 70 lb book (text/offset) stock
- Over 1 ounce up to 3 ounces: at least 80 lb stock
- Maximum weight for a folded self-mailer: 3 ounces
Can I use fugitive glue instead of tabs?
On a letter-size folded self-mailer, fugitive glue may be used instead of tabs to anchor the piece and inserts. If the bottom of the piece is open, inserts must be anchored in place with fugitive glue. Perforated tabs are not permitted under any configuration. A sheet folded to flat size is a flat and is prepared under flat standards (see Does a sheet folded to a flat size need tabs).
How tabbing affects your postage
Proper tabbing and folding qualify a self-mailer for letter-rate automation postage instead of the higher flat rate. On a large campaign the per-piece difference is substantial, so getting the tab count and placement right is a cost decision, not just a compliance one. If a design cannot meet these rules, bring it to a Plavidian rep rather than guessing.