A mailer box is a one-piece, self-locking box that folds up from a single sheet and is designed to be opened and displayed by the customer. A shipping box is a regular slotted carton, usually closed with tape, built mainly to move goods safely through the post. For most small online brands, a mailer box is the better choice when presentation matters, while a shipping box suits heavier or bulkier goods.
If you sell online in the UK, you will have met both styles. They look similar on a packing bench, but they behave very differently once a courier gets hold of them. This guide explains what separates them, when each one earns its place, and how to choose the right one for your products and budget.
What is a mailer box?
A mailer box (sometimes called a postal box or die-cut mailer) is made from a single piece of corrugated board. The lid tucks in at the front and side walls lock into place, so no tape or glue is needed to keep it shut. Because the walls fold over on themselves, the box feels sturdy for its weight, and it opens cleanly to reveal the contents.
That clean opening is why mailer boxes are popular for subscription products, gifts, cosmetics, candles and accessories. If you are weighing up where unboxing fits into your wider plans, our guide to subscription box packaging shows how much first impressions matter.
What is a shipping box?
A shipping box is the classic regular slotted container (RSC). It arrives flat, folds into a rectangle, and has four top flaps and four bottom flaps that meet in the middle. It is sealed with tape, which is how most warehouses and couriers expect to see a parcel.
Shipping boxes tend to be available in tougher constructions, including single wall boxes and double wall boxes, which makes them a sensible option for heavier items, stacked pallet loads and long journeys.
Mailer box vs shipping box: the key differences
- Construction: a mailer box is one piece with a tuck-in lid, while a shipping box has separate flaps that need tape.
- Presentation: a mailer box is designed to be opened as a moment in itself. A shipping box is functional first.
- Protection: a shipping box usually offers more strength for heavy goods, while a mailer box protects light and medium items very well when paired with a little void fill.
- Packing speed: mailer boxes fold up quickly without tape, which can save seconds on every order.
- Branding: the lid of a mailer box gives you a natural place for a logo or message that the customer sees immediately.
When a mailer box is the better choice
Choose a mailer box when your products are light to medium in weight, fairly compact and sold on the strength of their look. Typical examples include skincare, jewellery, stationery, small gifts and apparel. Our small parcel boxes and large letter boxes are good places to start, because they are sized with postal formats in mind.
Mailer boxes also work well for repeat customers. A tidy, branded box that arrives intact encourages reviews, photos and re-orders, which is often worth more than the small difference in unit cost.
When a shipping box is the better choice
A shipping box is the safer bet when the contents are heavy, awkward, or likely to be stacked in transit. It also suits businesses that ship a wide mix of products and want one familiar, flexible format. If your items are fragile, the box is only part of the answer, so read our advice on packaging fragile items for posting and our comparison of void fill options.
Does the box type affect postage cost?
Yes, but through size and weight rather than style. Carriers price parcels by dimensions and weight, and a box that is bigger than it needs to be can cost you more to send. Royal Mail publishes the size limits for each format on its small parcel page, so check the current limits before you finalise a box size. We also explain how courier pricing works in our post on volumetric weight, and our Royal Mail parcel sizes guide helps match a box to a format.
The sensible approach is to measure your product, add room for any protective material, and pick the smallest stock size that fits. Our guide to measuring internal and external dimensions will stop you ordering the wrong size.
How printing works on both box types
At Fast Printed Boxes we print full-colour CMYK, using water-based digital inkjet, directly onto ready-made stock boxes. Print sits within a defined area on the lid or top face, with a clear unprinted margin around it, and the rest of the box shows the natural board colour. That means clean logos and simple line art look especially good, particularly on kraft stock. If you are choosing between board colours, see our comparison of kraft and white cardboard boxes, and make sure your file is ready with our guide to print-ready artwork.
A quick checklist before you order
- Weigh and measure your product, including any inner packaging.
- Decide whether presentation or raw protection matters more for this product.
- Check the postal format and size limits you want to hit.
- Choose the board strength to match the weight and journey.
- Prepare simple, print-ready artwork for the lid area.
Frequently asked questions
Are mailer boxes strong enough for posting?
Yes, for the right products. Corrugated mailer boxes are built for the post and cope well with light to medium items. For heavy goods, or items that will be stacked, a stronger shipping box is usually safer.
Do mailer boxes need tape?
Usually not. The lid tucks into the front and the walls lock, so the box stays closed without tape. Some sellers still add a tamper-evident seal, but it is not needed to hold the box shut.
Which is cheaper, a mailer box or a shipping box?
It depends on size, board strength and quantity. Mailer boxes can save packing time because there is no taping, while simple shipping boxes can be cheaper per unit in some sizes. Compare the total cost, including labour and postage.
Can I print my logo on a mailer box?
Yes. We print full-colour artwork onto the lid of our stock boxes, inside a defined print area with an unprinted margin. You supply the print-ready artwork and we print it.
Which box type is better for e-commerce?
Neither is better in every case. Mailer boxes suit lighter, brand-led products, while shipping boxes suit heavier or mixed orders. Many shops use both, matching the box to the product.
Choose the right box for your brand
Whichever format fits your products, you can browse our full range of custom printed boxes or visit the Fast Printed Boxes homepage to see what is available. If you are not sure which size or style suits you, our e-commerce boxes are a good place to begin.