Why E-commerce Packaging Favors Square Shapes: From Robot Efficiency to Sustainable Development

During the recent holiday shopping peak, the average consumer likely overlooked a key detail in e-commerce: the shape of the package.

In the supply chain that efficiently moves products through e-commerce channels, square designs like corrugated boxes dominate. Some argue this form also benefits marketing and reduces shipping emissions.

In some cases, brands are shifting from flexible packaging to rigid square or rectangular packaging; sometimes, they return to corrugated boxes after using other packaging formats for a period. Performance, efficiency, and sustainability factors play a role in the "squaring" choice; flexible packaging is more easily crushed and shifted during transit than corrugated boxes.

But a key reason box-shaped packaging currently dominates e-commerce is: robots.

"E-commerce is becoming increasingly automated," said Leon Nicholas, Vice President of Retail Insights and Solutions at Smurfit Westrock. "Robots are generally better suited to handle square and precisely sized items."

Robots used in e-commerce fulfillment typically pick items using suction cups, and they often cannot grasp flexible packaging the way they can grasp corrugated boxes.

"Automating with mailers or any flexible packaging material is very difficult. Automation works best when items are rigid and square or rectangular," said Greg Walls, Vice President of Revenue at Pacurate, a corrugated box optimization software company.

Squaring is not just a design consideration for secondary packaging. As more products ship directly in their own packaging (SIOC mode), some brands are turning to rigid square or rectangular packaging. Consumer goods traditionally using flexible packaging, such as snacks or pet food, are in some cases starting to adopt corrugated boxes, which is well-suited for SIOC. Similarly, certain products historically sold mainly in bottles or cans, such as wine and laundry detergent, show a similar trend.

Additionally, for primary packaging, "we see a very interesting square packaging shift in the vitamin and mineral category, especially with newer brands like Olly and Natrol, particularly in the gummy segment," said Ron Sasine, advisor at Kearney's Product Excellence and Renewal Lab and former Senior Director of Packaging for Walmart's private brands.

Square shapes also suit omnichannel packaging, meaning "packaging that performs equally well on a shelf, on a pallet, in a locker, or during robotic picking," Nicholas said. This packaging value becomes prominent as more retailers pick and ship from store backrooms rather than using separate distribution centers.

"This ultimately will enable large retailers to get products to consumers in the shortest time and with the fastest delivery speed," Sasine said, noting that retail stores like Walmart, Kroger, and Whole Foods have adopted this model.

Data indicates e-commerce continues to thrive: RaboResearch's quarterly report released in December showed that adjusted North American e-commerce sales accounted for 16.2% of total retail sales, calling e-commerce "the most important driver of containerboard demand."

That same month, market research firm Smithers predicted that corrugated packaging will see the highest growth rate in e-commerce packaging, with a projected compound annual growth rate of9.5%. Previously, Smithers reported in 2023 that corrugated packaging was the most common e-commerce packaging type, accounting for80% market share。

Additionally, large retailers and e-commerce companies are increasingly automating their operations. Sources say these factors will increase reliance on square packaging (rather than round, irregular, or flexible packaging) in the coming years.

"Automation inherently prefers rectangular prisms," Sasine said. "Geometries that favor automation will become more important in the future. It will be a significant driver in primary and secondary packaging design."

Are you dense enough?

Although some companies prefer square packaging, "you don't want a square box full of air," Nicholas said. The industry is pushing for densification in packaging and shipping, which Nicholas calls "the war against air," to improve shipping sustainability, efficiency, and cost-effectiveness.

Dimensioning (calculating a package's weight and dimensional volume) is a key factor in supply chain planning, optimization, and cost.

"FedEx and UPS penalize customers who ship too much air... That's roughly the intent behind their so-called 'dimensional weight,'" said Walls of Pacurate. "If you ship less air, you waste less money and material."

Square packaging often achieves higher shipping density—as long as it fits the product. This is where "right-sizing" becomes important.

Manual packing stations in distribution centers typically only have a limited inventory of box sizes, while right-sizing equipment can form a minimal-size box around the product. This concept can also reduce or eliminate the need for void fill.

"Right-sized packaging is certainly a trend we are seeing... Shipping costs and fuel costs continue to rise, so these types of packaging initiatives receive more attention," said David Gray, Senior Vice President of Sales at Sparck Technologies, an automated packaging systems supplier. "Cost savings are the primary driver for customers adopting our solutions, but sustainability is also very important."

Right-sizing "is indeed more efficient in shipping because you're not shipping as much air—you can fit more boxes in a truck. This also reduces carbon emissions," said Xinnan Li, packaging and logistics analyst at RaboResearch.

Right-sizing can also reduce the amount of packaging material used, aligning with the sustainability goals of many brands and e-commerce providers. For example, Amazon has repeatedly emphasized its ongoing efforts inlightweighting and packaging reduction.

But not all box right-sizing efforts fully achieve the intended benefits. Li explained that in some cases, automated packing machines fold (rather than cut off and recycle) excess box material when right-sizing. Double-wall box panels, while producing smaller boxes for higher shipping density, do not fully support material reduction goals. Therefore, in terms of box material area, right-sizing's impact on "corrugated usage is not as significant as previously thought," Li said.

However, flexible packaging has not been pushed out of the market. Automation technology is advancing, making robotic picking faster and more precise, including grasping flexible or round objects. Many companies are also shifting to flexible packaging (plastic or fiber-based) to reduce overall packaging material usage.

Sources say these secondary packaging options are still used only for a portion of e-commerce shipments—such as mailers for clothing or small items—while corrugated boxes remain dominant.

"I'm sure plastic bags are being phased out. We see people moving to paper mailers," Walls said.

Marketing adjustments

Shifting from round to square primary packaging can also offer marketing advantages. Essentially, flat panels can display more information, while round packaging is limited. Consumers also react differently to various packaging shapes.

Sasine said that packaging research he was previously involved in found that changing an industry-standard tall, narrow box to a shorter, wider format would be more efficient and sustainable. However, consumers "perceived tall as a value driver and short as a lower-value product," he said.

Sometimes, consumers interpret shape changes as a sign of shrinkflation, Sasine said, citing the backlash over Tropicana's new juice bottle shape introduced in 2024, which is more rectangular than its previous iconic curved version. While the standard bottle did decrease from 52 ounces to 46 ounces, Tropicana said it had correspondinglylowered the manufacturer's suggested retail price。

"Getting consumers to understand what a format change means and why it's beneficial is ultimately the key factor," he said. "If consumers are unwilling to accept innovation, brand owners will eventually return to formats that consumers accept and understand."

Because higher density leads to smaller packaging sizes, "in some design transitions, you're dealing with a smaller 'billboard' for branding and messaging on the package," said Nicholas of Smurfit Westrock.

"That's part of the contradiction," he said. "Testing is needed to ensure shoppers remain engaged."

Nevertheless, strong expert predictions indicate that square packaging will not disappear in e-commerce.

"Will we see more square formats? Absolutely," Sasine said. "There's a lot to be said for three-dimensional squaring."