A mailer box sits between a shipping carton and a retail box. It is strong enough to travel through a parcel network on its own, yet it opens like a lidded gift box rather than a taped carton. That combination is why subscription brands and online stores use it so widely.
How a mailer box is built
The industry name for the classic mailer is a roll end tuck front style. It is cut from a single sheet of board and folds up without glue at the packing table:
- The side walls roll over on themselves, so each side is two layers of board thick and locks into slots in the base.
- The lid is hinged to the back wall and closes over the top.
- A front tuck flap slides down inside the front wall, and small dust flaps or ear locks keep the corners closed.
The iBox custom mailer boxes page describes this as a tab lock tuck feature that keeps the item protected and ready for mailing. Because the box ships to you flat, it stores in far less space than an assembled box.
Which board a mailer uses
Most mailers are corrugated board, a fluted layer glued between two flat liners. Fine flutes such as E flute are common because they fold crisply and give a smooth surface for print, while heavier flutes add crush strength for weightier products. Lighter items sometimes ship in paperboard mailers. The iBox mailer boxes page lists corrugated, paperboard and cardboard options. For what the flute letters mean, see what is flute in corrugated.
Where mailer boxes are used
- Subscription boxes, where the unboxing is part of what the customer pays for.
- Ecommerce orders for apparel, cosmetics, books and small electronics.
- Candles and other items that need inserts or dividers to stay put. The iBox candle mailer boxes page describes combining product packaging and shipping in one unit, with cardboard inserts that minimize movement.
- Influencer and press kits, where print inside the lid carries a message.
Strengths and limits
The double-thickness side walls make a mailer sturdy for its size, and the lid gives a clean reveal without a knife. The same folded construction uses more board than a plain slotted carton of the same inside size, so for large, heavy or purely functional shipments a standard shipping carton is often the better tool. Mailers suit small to medium products best.
Sizing a mailer box
Mailers are measured inside: length, then width, then depth, where depth is the wall height. The iBox page notes that mailers are quoted by internal dimensions because the inside has to clear the product plus any protective packing. Depth tends to hide the most wasted space, and parcel carriers bill on dimensional weight, so it is worth getting right. Common sizes and a measuring walkthrough are on mailer box dimensions.
Related terms
- E flute vs B flute: the two board grades most mailers use.
- What is a tuck flap: the flap that closes the front of a mailer.
- What is a box insert: how products are held in place inside.
FAQ
Does a mailer box need tape?
The tuck closure holds the lid shut on its own. Many shippers still add a seal sticker or a strip of tape so the customer can see the box has not been opened in transit.
Can a mailer be printed inside?
Yes. Inside print is a common request on mailers, because the customer sees the inside of the lid first. Ask for it on the quote.
Ordering a custom mailer
iBox makes mailers from 100 boxes per size and artwork. The die and plates, design support and US shipping are free, and a digital proof comes before printing. Send internal length, width and depth, the board you prefer if you know it, and whether you want print inside, through the quote form.
