Inside Diameter vs Outside Diameter in Reusable Packaging: Why It Matters More Than You Think

Understanding inside diameter vs outside diameter in reusable packaging can mean the difference between a seamless fit and costly inefficiencies.

At first blush, the definitions seem easy to grasp. Outside diameter refers to the external measurement of a container or packaging unit. It defines the physical footprint the packaging occupies in the handling and logistics environment. Inside diameter, on the other hand, is the internal dimensions of a container—the usable space available to hold products or internal dunnage.

But as I learned in the conversation that follows, few details are as deceptively simple—and as critically important—as understanding the nuances of inside diameter (ID) and outside diameter (OD). It’s a topic that reusable packaging veterans like Bob Klimko, Director of Market Development at ORBIS Corporation, have spent decades navigating. And as Klimko emphasizes, getting it wrong can cost you. Literally.

“It all comes down to design inputs,” Klimko says. “What are you trying to protect? Who’s going to touch it? What equipment will it interface with? You have to understand every point of contact the packaging will have throughout its lifecycle.”

Klimko, an industry expert with roots stretching back to the days of Lewis Systems and the early evolution of reusable packaging, insists that OD and ID shouldn’t be seen in isolation. Rather, they’re two sides of the same coin—and both must be considered through the lens of how a container lives, moves, and returns across the supply chain.

Packaging vs. Material Handling

“One of my colleagues once said the difference between packaging and material handling is ID and OD,” Klimko explains. “Packaging engineers focus on inside dimensions because the cubic volume determines how much product fits inside. But material handling engineers—and logistics people—focus on OD. That’s what determines whether your container fits on a pallet jack, through an automated system, or inside a trailer.”

That tension between ID and OD plays out differently across industries. In automotive, for example, ergonomics and cube efficiency must coexist. In pharmaceuticals, cold chain compliance might dominate. In e-commerce, the challenge may be balancing dimensional optimization with high-speed handling systems.

But no matter the vertical, Klimko maintains the same mantra: “The design input process is agnostic to industry. It just incorporates application-specific requirements.”

The $1 Million Mistake: A Real-World OD Lesson

Nothing illustrates the importance of OD more starkly than a case Klimko experienced firsthand.

“We designed a bulk container that had to fit inside field equipment. We did all our homework and field testing,” he says. “But after the first season, one of our customers told us, ‘Hey, it worked great—except it doesn’t fit in a small subset of our equipment.”

Despite trying to design a universal size, existing equipment can have varying requirements. To address the issue, ORBIS made some modifications that met the new requirements, while still satisfying the initial design. We worked quickly to make the changes and ensure seamless integration with equipment.

ID, OD, and Tolerance: It’s All in the Details

Beyond the obvious spatial considerations, tolerances and materials add layers of complexity. “Many of today’s containers are injection molded or thermoformed,” Klimko notes. “To get them out of the tool, you need draft angles—and those angles create different inside dimensions at the top and bottom.” That variance can significantly impact dunnage design and product fit.

“People forget about that,” Klimko says. “If you’re designing dunnage, you have to factor in those ID variances. You need the part to fit securely, but not so tight that it creates friction or damage.”

Material also matters. Plastic, metal, wood—each behaves differently under stress, and each has different tolerance ranges. “That’s why your design inputs must consider your materials from day one,” he adds.

In some cases, OD vs. ID trade-offs show up in unexpected ways, like whether to include handles.

“I remember back in 1989, we were designing our first straight-wall containers,” Klimko recalls. “The engineers were debating how much cubic volume to sacrifice for ergonomic handles.”

The solution? A compromise. ORBIS worked directly with Toyota’s safety team to ensure that the container could be used safely by operators wearing gloves. “They told us, ‘This is how big the handle needs to be, period.’ That was it. Product volume had to come second to ergonomics.”

Klimko held up one of those original containers during our call. “This one’s still in my office,” he laughs. “It’s got some stuff in it. Over-engineered maybe, but it works.”

Designing for Reuse: The Full Lifecycle

“Reusable packaging only works when people care as much about the container when it’s empty as when it’s full,” Klimko stresses. And that’s where OD considerations often make or break a system.

“You have to plan for the return trip,” he says. “A system might be great going out, but if you can’t nest or collapse it effectively, you’re shipping air on the way back.”

Straight-wall systems, once considered inefficient compared to nestable designs, gained traction when it became clear that for certain line-side applications, particularly in just-in-time operations like Toyota’s, they offered superior product protection and faster handling, even if they didn’t nest.

Optimization Tools and Old-School Wisdom

While today’s engineers benefit from 3D CAD software and finite element analysis (FEA) to optimize packaging design, Klimko says the fundamentals haven’t changed. “You can have the best tools in the world, but if you don’t start with solid design inputs, it won’t matter.”

And that means talking to the people on the floor.

“We always try to get feedback from the actual users, not just the managers,” Klimko says. “The people handling the containers day in and day out know where the friction points are. They know if your container’s too dense or awkward or heavy. That feedback is gold.”

Closing the Loop: Sustainability Begins with Basics

As regulations like Europe’s PPWR begin to take hold, the pressure to design efficient, sustainable systems will only intensify. Klimko believes reusable packaging is well-positioned—if the basics are respected.

“We’ve been in the sustainability business forever,” he says. “We just didn’t call it that. But if you don’t care about return logistics and empty container efficiency, you’re not really being sustainable.”

For Klimko, the lesson is clear. “You can’t shortcut the basics. OD, ID, tolerances, ergonomics—those are your foundations. Miss one, and it’s not just a bad fit,” he concluded. “It’s a lost customer, a bad reputation, and possibly a million-dollar mistake.”

As the reusable packaging industry welcomes a new generation of engineers, that advice couldn’t be more timely.

Sidebar:

Inside Diameter vs Outside Diameter in Reusable Packaging: Definitions and Importance

Here are the basics regarding inside diameter vs outside diameter in reusable packaging:

Outside Diameter (OD)

Definition

The outside diameter refers to the external measurement of a container or packaging unit. It defines the physical footprint the packaging occupies in the handling and logistics environment.

Importance

• Equipment Compatibility:
  Critical for ensuring that containers fit material handling equipment, including pallet jacks, conveyors, automated storage and retrieval systems (ASRS), and custom line-side gear.
• Automation and System Flow:
  OD must be tightly controlled to prevent jams or misalignment in automated systems.
• Transport and Storage Optimization:
  OD determines how well containers “cube out” trucks, ocean containers, and warehouse space—key to reducing transport and storage costs.
• Cross-System Compatibility:
  Must align with industry standards and legacy equipment; mismatches can lead to costly redesigns or field modifications.
• Safety and Human Interface:
  Impacts ergonomic factors such as aisle clearance, lift handling, and worker safety zones.
• Return Logistics Efficiency:
  Influences the ability to nest or collapse containers for efficient empty return trips—key to the sustainability and cost-effectiveness of reusable systems.
  

Inside Diameter (ID)

Definition

 The inside diameter refers to the internal dimensions of a container—the usable space available to hold products or internal dunnage.

Importance

• Product Fit and Payload Capacity:
  Defines the actual volume available for product loading. Directly impacts how many units can be shipped per container.
• Protection and Dunnage Design:
  Internal packaging, such as dunnage or trays, must be carefully designed to fit within the ID, especially when tolerances are tight.
• Material Behavior and Manufacturing Tolerances:
  ID can vary due to draft angles or shrinkage in molded containers. These variances must be anticipated during the design phase.
• Pack Density vs. Usability Trade-offs:
  Maximizing internal space must be balanced with ease of part removal and ergonomic handling, especially in automotive and line-side applications.
• Customization for Specific Applications:
  ID may need to meet special requirements in regulated industries like food, pharma, or electronics, such as insulation, sterility, or temperature control.
  

Iterative Design and Continuous Improvement

Small changes in ID can result in significant system-wide gains—or issues—requiring iterative feedback from real-world users during development.

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Rick LeBlanc

Rick LeBlanc, EMBA, is the founder and editor of Reusable Packaging News (subscribe to the free newsletter) and editor of Western Pallet Magazine. A supply chain journalist with more than 30 years of experience, he specializes in pallets, reusable packaging, material handling and related operations. Rick is co-author of Pallets: A North American Perspective and Pallets & Progress: A Collected History of Pallets and Palletized Handling 1922–1945. He is also an advisory board member of the Virginia Tech Center for Packaging and Unit Load Design. Read Rick’s full bio.