Tri-fold brochures are one of the most common brochures worldwide.
Tri-fold brochures are made out from a sheet of paper that is folded two times. Looking at the brochure inside, you fold the right panel inwards first, and then you fold the left panel, inwards as well, so that it sits on top of the right panel. Tri-folds have 6 panels to place information on - 3 "outside" panels and 3 "inside" panels. The 6 panels are almost* the same size.
The reading flow is somewhat a debate, even between graphic designers. Some people think the three inside panels should be read immediately after the cover, while others think the "2nd cover" panel should be read instead. The "2nd cover" panel is the one on the outside that's neither the front cover nor the back cover. Visually speaking, a viewer will see this "2nd cover" panel as soon as he starts unfolding the brochure.
Viewers are tempted to open these tri-fold brochures, as they cause intrigue. Tri-folds are suitable for high-impact designs.
Overall, tri-fold brochures are versatile and great for most marketing campaigns.
Standard tri-fold brochures
The standard tri-fold brochure is made out of a LTR-sized page which ends up in a folded brochure measuring 3.7" wide x 8.5" high. It is extremely popular, thin and convenient to carry. It is intended to be placed in holders ("brochure racks") or to be handed over to people. Also, it is ideal to put in folders, or as a more elegant alternative to the flyer in trade shows.
These brochures are economical to print since any digital printer can create a tri-fold by folding a standard-sized print (LTR-sized) in three. Of course, you can print tri-fold brochures at traditional printer stores. Some companies would even print them in-house, provided they have a good printer, though it's not recommended.
Self-mailer tri-fold brochures
As long as the folded size is good for the postal service, you can make the tri-fold a self-mailer. The back cover is then left for return address and postage stamps. This allows you to mail it without an envelope. We suggest a thick and robust paper stock if you opt for a self-mailer tri-fold, to prevent any damage.
Standard tri-fold brochures in non-US markets
Tri-fold brochures size wil vary in countries using DIN paper sizes. Instead of a LTR-sized paper sheet, DIN-A4 sized paper is used, measuring 297mm x 210mm. Folded size is usually 100mm x 210mm.
Large tri-fold brochures
The tri-fold morphology adapts to any size, but it's specifically good for larger, more corporate-looking brochures. We call them large tri-folds, and they are usually made out of triple-LTR (25.5" x 11") or double-LTR (17" x 11") sheets of paper. The stock used for these large brochures is of higher quality than the standard tri-fold. They are more expensive to print and, depending on size, you may need to print them at professional printer stores.
*One of the "flaps" is slightly thinner (0.1" or so, depending on the printer) so it can be folded inside the other two.