Blog

• Match box type to product weight and value: mailer boxes for lightweight items under around 2 kg, standard corrugated (RSC) boxes for heavier or bulk orders
• Courier and delivery costs are usually based on volumetric (dimensional) weight, not just actual weight, so an oversized box increases cost even for a light product
• Self-locking mailer boxes remove the need for tape and packing time, which matters for sellers packing a high volume of orders
• Leave enough clearance for cushioning material, but no more, since excess empty space increases both damage risk and volumetric weight cost

What Are the Best Boxes for Packaging Online Orders?

Two box types cover most online order packaging needs. A corrugated mailer box is a self-locking, foldable box with built-in flaps, designed to ship directly as the outer package while still allowing exterior and interior branding. A standard Regular Slotted Carton (RSC) is the more familiar taped shipping box, better suited to heavier, bulkier, or multi-item orders. Choosing between them depends mainly on product weight, fragility, and how many units are shipped per order.

Mailer Box vs Corrugated Box for E-commerce, What Is the Difference?

Mailer boxes use thinner corrugated boards, generally E-flute or B-flute, which keeps them light and gives a clean, printable surface suited to a polished unboxing experience. Standard corrugated boxes use thicker board and are built for durability under stacking and rough handling rather than presentation. As a working guide, mailer boxes suit single-item or lightweight orders such as apparel, cosmetics, accessories, and books, while standard corrugated boxes suit heavier products, multi-item orders, and anything shipped in bulk to a single destination.

What Size Box Should You Use for Shipping Online Orders?

Box size should be based on the product’s actual dimensions plus clearance for cushioning, not a single generic size used for every order. A box with too much empty space allows the product to shift during transit and increases the chance of impact damage. It also means paying for space that is not being used. A snug fit, with roughly a quarter to half an inch of clearance per side for smaller items and more for fragile or irregular products, keeps both damage risk and unused volume to a minimum.

Online sellers shipping a narrow range of product types benefit from standardising on two or three box sizes matched to their most common orders, rather than sourcing a new size for every product variation. This keeps packing consistent, reduces the number of box sizes that need to be kept in stock, and makes it easier to forecast packaging costs against order volume.

How Does Box Size Affect Courier Shipping Cost?

Most couriers price parcels using volumetric weight, calculated from the box’s length, width, and height, rather than actual product weight alone. This means a large box holding a light product can be charged at a higher rate than its actual weight would suggest, since the courier is pricing the space the parcel occupies rather than what is inside it. Reducing box size to match the product, rather than defaulting to one oversized box for convenience, directly reduces this cost across a high volume of orders.

This cost difference compounds at scale. A seller shipping a few hundred parcels a month absorbs the cost of oversized boxes as a fixed inefficiency in every order, not just an occasional one. Reviewing box size against actual order dimensions on a regular basis, particularly after adding new product lines, helps catch cases where a box originally chosen for one product is being reused for a smaller item it was never sized for.

Should You Use a Self-Locking Box or a Taped Box for Online Orders?

Self-locking mailer boxes close using built-in tabs and flaps, removing the need for tape entirely. This reduces both material cost and the time needed to pack each order, which becomes significant at higher order volumes. Standard taped RSC boxes remain necessary for heavier loads, since a self-locking closure is not built to hold the same weight securely during transit. The H-taping method, running tape along all seams rather than just the centre seam, remains the standard for any taped box carrying a heavier or bulk order.

How Much Cushioning Does an Online Order Need?

Cushioning needs depend on product fragility rather than weight alone. Products that can withstand moderate handling, such as folded apparel or books, need minimal cushioning beyond a well-fitted box. Fragile or breakable items need a cushioning material such as paper fill, air pillows, or bubble wrap to prevent contact between the product and the box wall during transit. Filling excess space in an oversized box with cushioning material is a less effective and more costly substitute for simply using a correctly sized box in the first place.

When to Use a Mailer Box vs a Standard Shipping Box

A mailer box works well as both the shipping box and the customer-facing package for direct-to-consumer orders where presentation matters, such as apparel, cosmetics, or gift items. A standard shipping box is the better choice for wholesale or bulk orders, multi-item shipments, or products where structural strength matters more than unboxing presentation. Businesses running both a retail e-commerce channel and a wholesale channel typically need both box types rather than standardising on one.

For online sellers and businesses in Sri Lanka packing a growing volume of orders, EZI Packaging manufactures corrugated boxes and mailer-style cartons sized to specific product dimensions, reducing both damage risk and courier cost per parcel. Send an inquiry with your average order size and monthly volume for a box specification recommendation.

Frequently Asked Questions