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Sustainability Simplified™ | Sustainability Basics

Understanding Sustainable Material Accounting

What Is Mass Balance in Packaging?

Mass balance is an accounting and chain-of-custody approach used to track and allocate recycled, renewable or other preferred feedstocks when they are mixed with conventional materials in a shared production system.

Quick Answer Mass balance allows a manufacturer to introduce a measured amount of recycled or renewable feedstock into a shared production system and allocate an equivalent amount of that input to selected products according to an established accounting method.

It does not necessarily mean the exact recycled or renewable molecules can be physically identified in the specific package receiving the mass-balance attribution.

Mass balance is commonly discussed in connection with chemical recycling, advanced recycling and bio-based feedstocks because these materials may be processed together with conventional feedstocks in large integrated manufacturing systems.

How Mass Balance Works What It Means for Packaging Claims
Mass Balance Image Placeholder Show recycled or renewable feedstock and conventional feedstock entering one shared production system, followed by multiple outputs with an accounting allocation applied to selected packaging.

The Fundamental Concept

What Does Mass Balance Mean?

Mass balance is used when different feedstocks are combined within the same manufacturing system and cannot remain physically separated throughout the entire process.

Instead of tracking individual molecules from input to finished package, the system tracks the quantity of qualifying feedstock that enters production and allocates an equivalent quantity to specified outputs using defined accounting rules.

This creates a documented chain of custody between the amount of qualifying material introduced and the amount attributed to products leaving the system.

Packaging Example

Example: Recycled Feedstock in a Shared Resin System

A resin producer may introduce a verified amount of recycled feedstock into a production system that also processes conventional feedstock.

Because the materials are mixed within the system, the recycled molecules may not be physically traceable to one specific batch of finished packaging resin.

Key takeaway: Mass balance tracks the quantity and allocation of qualifying feedstock. It does not necessarily represent direct physical segregation of that material in a specific finished package.

A Simplified Accounting Pathway

How Does Mass Balance Work?

The exact rules depend on the certification program, supplier and production system, but the basic concept can be simplified into five stages.

1
Qualifying Feedstock Recycled, renewable or other qualifying feedstock enters the system.
2
Conventional Feedstock Conventional materials may enter the same shared production system.
3
Shared Processing Feedstocks are processed together within an integrated system.
4
Accounting Allocation The verified qualifying input is allocated to selected outputs.
5
Documented Product Eligible products receive an attributed claim supported by records.

The Most Important Distinction

Physical Recycled Content vs. Mass-Balance Attribution

These concepts should not be treated as interchangeable. One describes physically incorporated recycled material, while the other describes an allocation through an accounting system.

Question Physical Recycled Content Mass-Balance Attribution
What does it represent? Recycled material physically incorporated into the specific resin or package. A documented allocation of qualifying feedstock through a shared production system.
Can the material remain segregated? It may be physically traceable through a dedicated or segregated material stream. The qualifying feedstock may be mixed with conventional feedstock during production.
Can exact molecules be identified? The recycled resin is physically present in the package. Exact qualifying molecules may not be identifiable in the specific finished package.
How is the claim supported? Material specifications and recycled-content documentation. Chain-of-custody records, accounting rules and applicable certification or supplier documentation.

Why It Exists

Why Is Mass Balance Used?

Some manufacturing systems operate at a scale or level of integration where fully separating recycled, renewable and conventional feedstocks throughout production may be difficult or impractical.

Mass balance provides a documented method for introducing qualifying feedstock into those shared systems while tracking how the associated material value is allocated to finished products.

Shared Infrastructure
Mixed Feedstocks
Verified Inputs
Documented Allocation
Traceable Claims

A Common Connection

Why Is Mass Balance Often Associated With Chemical Recycling?

Chemical-recycling processes can create feedstocks that may enter large petrochemical and polymer-production systems alongside conventional feedstocks.

Once those materials are combined within an integrated manufacturing system, physically tracking individual recycled molecules to a specific package may not be practical.

A mass-balance system can therefore be used to track the qualifying recycled feedstock introduced and allocate the corresponding quantity to eligible resin or packaging outputs.

Chemical Recycling + Mass Balance Placeholder Show plastic waste converted into feedstock, then entering a shared resin-production system with conventional feedstock, followed by allocated packaging outputs.

Packaging Claims Matter

What Does Mass Balance Mean for Packaging Claims?

Mass-balance claims should clearly communicate what is being attributed and how that attribution is supported.

Understand the Claim

Determine whether the supplier is describing physical recycled content, attributed recycled feedstock or another chain-of-custody approach.

Review Documentation

Confirm what documentation, certification or supplier records support the claimed allocation.

Avoid Overstatement

Claim language should not imply direct physical recycled content if the claim is based on mass-balance attribution.

Identify the Accounting Model

Understand how qualifying inputs are tracked, converted and allocated to outputs.

Confirm Certification Scope

Verify what facilities, feedstocks, processes and products are included within the applicable certification or chain of custody.

Match the Market

Claim requirements and acceptable terminology may vary by market, customer and regulatory environment.

Important Clarifications

What Does Mass Balance Not Automatically Mean?

“The specific package contains the exact attributed percentage of recycled molecules.” Not necessarily. Mass balance is based on documented input and allocation rather than molecule-by-molecule physical tracing.
“Mass balance and physical PCR are the same thing.” No. Physical PCR refers to recycled material physically incorporated into a package. Mass balance is a chain-of-custody accounting approach.
“Any company can make a mass-balance claim without documentation.” Credible claims should be supported by appropriate records, chain-of-custody controls and applicable certification or supplier documentation.
“Mass balance automatically proves a package is more sustainable.” No. Overall environmental performance depends on the complete system, including feedstocks, processing, energy, transportation, package performance and end-of-life pathways.

Practical Packaging Questions

What Should Manufacturers Ask a Supplier?

What Is Being Attributed?

Ask whether the claim relates to recycled feedstock, renewable feedstock or another material source.

What Certification Is Used?

Ask what certification, audit system or chain-of-custody standard supports the claim.

How Is Allocation Calculated?

Understand the supplier's allocation method and how qualifying material moves through the accounting system.

What Documentation Is Available?

Request appropriate supporting records for internal review and downstream claims.

What Can We Claim?

Confirm the exact language the documentation supports before using environmental marketing claims.

Does the Package Still Perform?

Sustainability attributes should still be evaluated alongside product compatibility, performance, supply and cost.

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Sustainability Simplified™ in Under a Minute

What Is Mass Balance?

Suggested Narration

“Mass balance is an accounting method used when recycled or renewable feedstocks are mixed with conventional materials in a shared manufacturing system. The amount of qualifying material entering the system is tracked and an equivalent amount can be allocated to selected products. That does not necessarily mean the exact recycled molecules are physically present in the specific package receiving the claim.”

When the video is published, include the transcript as HTML text on the page so visitors and answer engines can access the information.

Sustainability Simplified™ — At a Glance

Three Things to Remember About Mass Balance

It Is an Accounting Approach Mass balance tracks qualifying feedstock through a shared production system using defined allocation rules.
It Is Not the Same as Physical PCR The attributed recycled feedstock may not be physically identifiable in the specific finished package.
Documentation Matters Claims should be supported by clear chain-of-custody records, certification and appropriate supplier documentation.

Frequently Asked Questions

Mass Balance FAQs

What is mass balance in packaging?
Mass balance is an accounting and chain-of-custody approach used to track and allocate recycled, renewable or other qualifying feedstocks when they are mixed with conventional materials in a shared production system.
Does mass balance mean recycled plastic is physically in the package?
Not necessarily. Mass balance tracks the quantity of qualifying feedstock introduced into a production system and allocates an equivalent quantity to selected outputs. The exact recycled molecules may not be physically traceable to the specific package.
Is mass balance the same as PCR?
No. PCR generally refers to post-consumer recycled material that is physically incorporated into a product or package. Mass balance is an accounting approach that allocates qualifying recycled or renewable feedstock through a shared system.
Why is mass balance used with chemical recycling?
Chemical-recycling feedstocks may enter large integrated manufacturing systems alongside conventional feedstocks. Mass balance can track the qualifying recycled input and allocate the corresponding quantity to selected outputs even when the feedstocks are physically mixed.
What is a mass-balance claim?
A mass-balance claim indicates that a defined quantity of qualifying material has been attributed to a product through an approved accounting and chain-of-custody system. The exact meaning depends on the applicable certification, supplier documentation and claim rules.
Can mass balance be used for renewable feedstocks?
Yes. Mass-balance systems can be used to track different qualifying feedstocks, including certain recycled and renewable inputs, depending on the production system and applicable certification scheme.
Does mass balance make packaging recyclable?
No. Mass balance describes feedstock accounting and attribution. Recyclability is a separate consideration involving package design, material compatibility, collection, sorting and recycling infrastructure.
What should manufacturers verify before making a mass-balance claim?
Manufacturers should understand the feedstock being attributed, the accounting method, certification scope, supplier documentation and the exact claim language supported for the package and intended market.

Understanding Sustainable Material Claims

A Sustainability Attribute Is Only Useful If You Understand What It Actually Means.

Empire EMCO helps manufacturers evaluate rigid packaging options based on resin, recycled content, mass-balance documentation, package performance, product compatibility, supplier capabilities, sourcing, cost and sustainability goals.

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Educational Information: Sustainability Simplified™ provides general packaging education and is not intended as legal, regulatory, certification, chain-of-custody or environmental-claims advice. Mass-balance rules, certification schemes, allocation methods, documentation requirements and acceptable claim language can vary by supplier, program, application and market. Manufacturers should confirm current requirements and review appropriate documentation before making environmental or recycled-content claims.