How to Choose the Right Box for E-Commerce Shipping

The wrong box costs you money on every single shipment — in wasted materials, dimensional weight fees, and damaged product returns. Here's how to spec the right mailer or shipper box for your e-commerce operation.

Most e-commerce brands ship in one of two formats:

• Mailer boxes (also called "e-commerce boxes" or "subscription boxes") — rigid, custom-printed, self-locking boxes that fold flat for storage. They open dramatically, making them ideal for the unboxing experience. Best for lighter products, apparel, beauty, and anything where presentation matters.
• RSC shipper boxes (Regular Slotted Cartons) — the classic brown corrugated shipper. More protective for heavier or fragile products. Can be printed on the outside for brand visibility.

The choice between them depends on your product weight, fragility, and how much the unboxing experience matters to your brand.

Canada Post, Purolator, UPS, and FedEx all charge based on dimensional weight (DIM weight) — not just actual weight. DIM weight is calculated as: Length × Width × Height ÷ 5,000 (in centimetres). If your box's DIM weight exceeds its actual weight, you pay the DIM rate.

This means oversized boxes cost you money even if your product is light. A box that's 5 cm too wide in each dimension can add $2–$5 per shipment in DIM charges — which compounds fast at volume.

The fix: spec your box as close to your product dimensions as practical. When you request a quote from us, give us your product dimensions and we'll recommend the right box size.

Mailer boxes are measured by interior dimensions: Length × Width × Depth. Always spec based on what needs to fit inside, not the outside of the box.

Common mailer box sizes for Canadian e-commerce brands:

• Small (20×15×8 cm): Jewellery, small cosmetics, accessories
• Medium (30×22×10 cm): Apparel (folded), books, subscription boxes
• Large (35×25×12 cm): Multiple items, larger apparel, home goods

If your product dimensions don't fit a standard size, we can produce custom sizes — include your product dimensions in the quote form.

Mailer boxes are typically made from E-flute or B-flute corrugated board, or from rigid paperboard (sometimes called "rigid box" style). Here's the difference:

• E-flute corrugated: Lightweight, good crush resistance, excellent print surface. The most common choice for e-commerce mailers. Ships flat.
• B-flute corrugated: Thicker, heavier, more protective. Better for fragile or heavier items. Slightly less refined print surface.
• Rigid paperboard: Premium feel, excellent print quality, used for luxury unboxing. Does not ship flat — more expensive to warehouse and ship.

For consumer brands, the box is part of the product. Custom printing on the outside creates a brand moment at the doorstep. Printing on the inside lid creates a second surprise moment on open.

Details that elevate the unboxing experience without major cost increases: full-colour exterior print, interior colour or spot pattern, tissue paper or branded void fill, a simple insert card. None of these require a massive budget — and all of them drive social sharing and repeat purchase.

• Measure your product at its largest point (including any packaging it arrives in)
• Add 1–2 cm clearance on each dimension for void fill or tissue
• Check the DIM weight of your target box size with your carrier
• Decide whether you need interior printing or just exterior
• Confirm whether your product needs additional protection (inserts, foam, dividers)
• Order a small run first to test before committing to larger quantities