Mailer Boxes, Postal Boxes and Paper Mailers

What counts as a mailer or postal box?

A mailer box is a one-piece folding box that travels on its own, with no outer carton. The usual design has a lid hinged at the back that tucks into the front, and side walls that roll over for double thickness.

Postal boxes are the broader family. They include end opening boxes, side loaders and crash-lock styles, all sized for the post. This range also holds paper and film mailing bags for goods that do not need a rigid box.

Everything here folds or lies flat until you need it, which saves space at the packing bench. Each order is cut to your own size, so there is no picking the nearest stock box and filling the gap.

For the classic tuck front style that most shops start with, see our custom printed mailer boxes page.

All seventeen mailers compared

The first two columns tell you what each style is for. The key detail column shows how it opens, closes or protects.

Box, bag or padded mailer?

A box gives shape and stacking strength. Choose one for anything that can crush, scratch or break, and for orders where presentation matters.

A paper or film bag is lighter and flatter. That can drop a parcel into a smaller postage band, which adds up over hundreds of orders. Soft goods such as T-shirts and knitwear travel well in a bag.

Padded paper mailers sit in between. They suit small, firm items that need a little cushioning but not a box. Our padded paper mailers lined with paper page explains how the cushioning layer works.

Sizing a mailer so it posts cheaply

Mailers work best when they fit closely. Measure the goods, add a few millimetres for tissue or an insert, then send us the three inside measurements.

Height matters most for postage. A box that is 10 mm too deep can move into a dearer size band and cost more on every order. For tiny goods, our small mailing boxes for compact goods keep parcels slim.

For bags, give the flat width and length. Allow for the thickness of the goods, since a bag loses usable size as it fills.

If you sell in several sizes, try to fit two or three products into one box size. Fewer sizes mean longer runs, which lowers the price of each box.

Board choices for mailer boxes

Most mailers use single wall E flute, about 1.5 mm. It folds sharply, prints cleanly and keeps the box light. B flute, about 3 mm, suits heavier goods or bigger boxes.

For glass, ceramics and heavy gift sets, a double wall BC mailer at about 7 mm gives far more crush resistance. Our fragile item mailers for breakables combine thicker board with inner support.

Kraft and white liners are both available. White shows colour print brighter, while kraft suits a single ink on a brown, natural surface.

Printing inside and outside a mailer

A mailer is often the first physical contact a customer has with your brand. Printing the outside makes the parcel easy to spot on the doorstep, and printing the inside gives a moment of surprise when the lid lifts.

Leave it blank, use one or two inks, or go full CMYK, on either face. Finishes such as matte or gloss lamination, spot UV and foil add a premium feel. See our double sided printed mailers for ideas on using both faces.

Every job gets a free digital proof first, and a designer will tidy up the layout free of charge.

Mailer mistakes that cost money

The most expensive mistake is a box that is slightly too large. It needs filler, looks loose when opened, and may cost more to post. Measure twice before you order.

Another is choosing a heavy board for light goods. E flute is enough for most cosmetics and clothing, and it keeps the parcel weight down.

For multi-item kits, a loose box lets pieces knock together. A cut-out insert stops that. Our mailer boxes with fitted inserts are made with the insert sized to each item.

Last, think about the unboxing order. Put the thank-you card or leaflet on top so it is the first thing seen, not something found later at the bottom of the box.

Paper and film mailing bags

Not every order needs a box. Kraft paper mailers are flat paper bags with a seal strip, and they suit clothing, books and prints. Padded paper mailers add a cushioning layer inside.

Compostable mailers swap normal polythene for a film that can be composted. We name the film and the disposal advice on the quote. Our kraft paper mailers for soft goods are the simplest all-paper option.

Bags are sized by their flat width and length. They print well in one or two colours, and full colour is available on paper styles.