Mailer Boxes vs Shipping Boxes vs Corrugated: Which Custom Box Do You Need?
The Three Box Types Every Business Should Know
Ordering custom boxes starts with one critical question: which box type? Mailer boxes, shipping boxes, and corrugated boxes each serve different purposes, and picking the wrong one costs money — either through over-engineering (paying for protection you dont need) or under-engineering (returns from damaged goods).
Here is the breakdown your packaging vendor probably skipped.
Mailer Boxes: The Unboxing Box
Mailer boxes (also called tuck-end or self-locking mailers) are E-flute corrugated at 1.5mm thickness. They ship flat, pop into shape with no tape needed, and are the standard for DTC e-commerce brands.
Key Facts
- Flute: E-flute (1.5mm)
- Weight capacity: Up to 8 lbs
- Printing: Full CMYK on exterior and interior
- Cost: $0.75-$3.50/unit at 1,000 units
- Best for: Subscription boxes, cosmetics, apparel, small electronics
Mailer boxes prioritize brand experience over protection. The full-color interior print creates Instagram-worthy unboxing moments. But at 1.5mm, they are not built for heavy items or stacking.
When to choose a mailer box: Your product weighs under 8 lbs, ships individually (not palletized), and brand presentation matters more than maximum protection. See our custom mailer boxes.
Shipping Boxes: The Workhorse
Shipping boxes (RSC — Regular Slotted Container) are the brown boxes you see in every warehouse. B-flute (3mm) or C-flute (4mm), they are designed for stacking, palletizing, and protection.
Key Facts
- Flute: B-flute (3mm) or C-flute (4mm)
- Weight capacity: 20-65 lbs (ECT-29 to ECT-32)
- Printing: 1-4 color flexo, or litho-laminated for full color
- Cost: $0.50-$2.50/unit at 1,000 units
- Best for: E-commerce fulfillment, wholesale, heavy items, stacking
RSC boxes require tape to close — they dont self-lock like mailers. But they handle more weight, stack better, and cost less per unit.
When to choose a shipping box: Your product is heavy (over 8 lbs), ships in quantity (palletized), or needs to stack in a warehouse. Cost matters more than unboxing experience. See our custom shipping boxes.
Corrugated Boxes: The Whole Family
Here is what most guides get wrong: mailer boxes and shipping boxes are both corrugated boxes. Corrugated just means the material has a wavy fluted layer between two liners. The term "corrugated box" encompasses the entire family.
But when people search for "custom corrugated boxes," they typically mean industrial-grade packaging: double-wall, triple-wall, or specialty corrugated for heavy or fragile items.
Key Facts
- Flute: BC double-wall (7mm) or triple-wall (15mm)
- Weight capacity: 65-300+ lbs
- Printing: Flexo, litho-laminated, or digital
- Cost: $2-$15/unit at 500 units
- Best for: Industrial parts, machinery, produce, electronics, replacing wooden crates
When to choose industrial corrugated: Your product exceeds 65 lbs, needs maximum protection, or replaces wooden crates. See our custom corrugated boxes.
Side-by-Side Comparison
| Feature | Mailer Box | Shipping Box (RSC) | Industrial Corrugated |
|---|---|---|---|
| Thickness | 1.5mm (E-flute) | 3-4mm (B/C-flute) | 7-15mm (double/triple) |
| Max Weight | 8 lbs | 65 lbs | 300+ lbs |
| Closure | Self-locking tabs | Tape required | Tape + banding |
| Interior Print | Full CMYK | Limited | Limited |
| Cost (1,000 units) | $0.75-$3.50 | $0.50-$2.50 | $2-$15 |
| Ships Flat | Yes | Yes | Some styles |
| Stacking Strength | Low | High | Very High |
| Best For | DTC/Unboxing | Fulfillment | Industrial |
Which Box Should You Choose?
Choose a mailer box if: You sell DTC, ship individual orders, and your product weighs under 8 lbs. Brand experience is your priority.
Choose a shipping box if: You ship in bulk, palletize orders, or need cost-effective protection for 8-65 lb items.
Choose industrial corrugated if: Your product exceeds 65 lbs, is fragile and valuable, or currently ships in wooden crates.
Pro tip: Many brands use both — a branded mailer box inside a plain shipping box. The outer box handles logistics; the inner box handles the brand experience. This "box-in-box" strategy costs $1-3 more per shipment but significantly reduces damage claims.
Frequently Asked Questions
What is the difference between a mailer box and a shipping box?
A mailer box is E-flute corrugated (1.5mm) with self-locking tabs and full-color printing on both sides. A shipping box (RSC) is B or C-flute (3-4mm) with tape closure and typically 1-4 color flexo printing. Mailer boxes prioritize brand experience; shipping boxes prioritize protection and stacking.
Can I print full color on shipping boxes?
Yes, through litho-lamination — a full-color printed paper is laminated onto the corrugated board. This costs more than standard flexo printing but delivers photographic quality on any flute type. Learn more about our corrugated printing options.
What ECT rating do I need?
ECT-23 for items under 20 lbs, ECT-29 for 20-40 lbs, ECT-32 for 40-65 lbs, and ECT-44+ for heavy industrial loads. Most e-commerce ships with ECT-32 B-flute.
Get Started
Not sure which box type fits your product? Our custom packaging consultant analyzes your product dimensions, weight, and shipping method to recommend the right box. Or browse all options:
- Custom Mailer Boxes — from $0.75/unit
- Custom Shipping Boxes — from $0.50/unit
- Custom Corrugated Boxes — from $2/unit
