Slack Fill: Reducing Risks and Improving Bottom Line Profits

By Bob Fiedler, Principal, Packaging Optimization

Have you ever opened up a package and noticed that it’s only half full of product? Well, all that empty space inside the package is considered slack fill. Slack fill is defined as the difference between the actual capacity of a container and the volume of the product it contains.

The Code of Federal Regulations “Title 21 – Food and Drugs, Section 100.100 – Misleading containers” defines the issue. “In accordance with section 403(d) of the act, a food shall be deemed to be misbranded if its container is so made, formed, or filled as to be misleading.”

“A container that does not allow the consumer to fully view its contents shall be considered to be filled as to be misleading if it contains nonfunctional slack-fill. Slack fill is the difference between the actual capacity of a container and the volume of product contained therein. Nonfunctional slack fill is the empty space in a package that is filled to less than its capacity for reasons other than:”

The list of federal exceptions is short but informative. A brief summary includes such things as: product protection, machine limits, product settling, required package functions, etc. This full list of federal exceptions needs to be studied in detail.

If it looks deceptive, it probably is … 

The bottom line is, if it looks “misleading” you need to have your ducks in a row or the State Attorneys General will be giving you a call to see if they can capture some fines at your expense. Fines of $2,000 per package with $200,000 to $300,000 settlements have been noted, with the state of California leading the charge in the crackdown against consumer goods producers who have been deceivingly underfilling their packaging. In fact, many CPG’s settle out of court to keep their violation out of the public eye and minimize the potential backlash from their misleading ways.

The absence of any hard and fast rules defining what is “misleading” further increases risk. A good rule of thumb is that if it looks deceptive, it probably is at risk. A defense that the weight of the contents of the package are clearly labeled on the outside of the package is insufficient. This is the minimum required by the “weights and measures” laws which, if ignored, will and often does result in significant fines and impounding of products.

Where some companies run into clearly misleading slack fill complaints is when they try to “package to price” – using the same size package but reducing the amount of product. This may be to keep the price below an acceptable competitive level or to offset increased product costs. In recent years many companies have been noted to decrease their selling unit size (and usually their packaging size as well) —- see Tropicana Consumer Report Example . If the package previously held more product, reducing the product content without also reducing the package size is blatantly misleading.

Rigid packages are at most risk for being misleading in that they are often opaque preventing visibility of the product. The package is also a fixed capacity and the slack fill can be accurately measured. It is more difficult to define the “actual capacity” of flexible packaging as this may be alternately defined as the “maximum” capacity of a bag or the “used” capacity of a bag as sold.

Slack fill variations may be the result of product and package variations and limitations. Issues such as varying product densities, shapes, and fill characteristics may demand greater slack fill to functionally address the variations.

Likewise, packaging equipment limitations and operating speeds may require more flexibility in fill levels. The slack fill may also change over time due to settling during handling or expansion due to pressure changes. Knowing your system variations will help to optimize systems for maximum customer satisfaction and profitability.

Addressing slack fill risks has a green upside in dollars saved and environmental benefits

One of the benefits of addressing slack fill risks is discovering the opportunities that become evident. The cost of packaging and shipping “air” vs. sellable product is almost the same. However, only “product” sales produce value to customers and profits. Significant packaging supply chain savings opportunities can be discovered and implemented at the same time slack fill issues are addressed by reducing the primary package size, improving case efficiencies and pallet load utilization. One small change in primary packaging can lead to a huge cascade of savings across your supply chain – including packaging materials, logistics, warehouse and labor savings.

Primary packages directly drive the costs of distribution packaging and required transportation, handling and storage costs. A 10 to 15 percent size reduction of a primary package by reducing slack fill, may be leveraged into 10 to 15 percent savings in packaging materials both primary and secondary, material handling, storage and most importantly transportation costs. This may further result in more product facings, fewer stock outs in stores, faster turns and better customer satisfaction. The average trailer on the highway is over 30 percent empty by weight filled with unnecessary “air” inside packages with slack fill and underfilled cases. Taking advantage of the unused trailer capacity that is already paid for is a direct bottom line win.

Want to ship less air, and drive profits higher?

Is your packaging a slack fill risk? Best to know the results before the attorneys general do. The Packaging Practice of Chainalytics is dedicated to looking inside the box to address risks and opportunities. Chainalytics engineering resources have processes and procedures in place to analyze and audit your products’ slack fill risk and can develop a go forward plan to help mitigate the risk. We have saved companies countless trailer loads of shipping air while addressing risks associated with products inside.

Want to ship less air and limit risk  while embarking on a simultaneously “green” AND profitable venture?

Contact the packaging engineers at Chainalytics at or give us a call at +1 612.252.1830.

In this article