Material Flow Analysis (MFA)
The diagnostic tool of the circular economy
Material Flow Analysis (MFA) is the systematic tracking of material inputs, stocks, and outputs through a defined system over a defined period. It is the analytical foundation of the Circularity Gap Report and the primary tool used by governments and companies to diagnose where materials are lost, where circular strategies can intervene, and how much circularity improvement is actually achievable.
What MFA Measures and Why It Matters
In plain terms, Material Flow Analysis is an accounting system for physical stuff. Just as financial accounting tracks the flow of money through an organisation, MFA tracks the flow of materials through an economy, a sector, a city, or a company. The goal is to understand where materials come from, where they go, and where they are lost before their potential value is extracted.
Without this diagnostic picture, circular economy interventions are essentially guesswork. MFA reveals which waste streams are largest, which materials are most technically recoverable, where supply chains leak value, and what the theoretical maximum circularity improvement might be. It converts vague commitments to "be more circular" into specific, measurable targets grounded in material reality.
Analogy: MFA as a Metabolic Scan
A doctor cannot improve a patient's metabolism without first understanding how it currently works: what the patient eats, how nutrients are processed, where they are stored, and what is excreted. Material Flow Analysis does the same for an economy: it maps inputs (extraction and imports), internal transformation (manufacturing and use), stocks (products and infrastructure in use), and outputs (emissions, waste, and exports). Without this metabolic picture, circular economy prescription is blind.
The Structure of an MFA
A standard material flow analysis comprises four basic elements:
| Element | Definition | Example |
|---|---|---|
| Inputs | Materials entering the system from outside | Domestic extraction of iron ore; imports of aluminium ingots; recycled scrap steel |
| Stocks | Materials accumulating within the system in long-lived products or infrastructure | Steel in buildings, vehicles, and appliances currently in use |
| Outputs | Materials leaving the system as waste, emissions, or exports | CO2 emissions from steel production; scrap exported for recycling abroad; landfilled construction waste |
| Flows | Movement of materials between processes within the system | Iron ore to blast furnace to crude steel to rolling mill to automotive stamping plant |
How the Circularity Gap Report Uses MFA
The Circularity Gap Report, produced annually by Circle Economy Foundation, applies MFA at the global scale to track the Circularity Rate: the share of secondary (recycled or recovered) materials entering the global economy as a proportion of total material consumption. The 2024 report found this rate to be 7.2%, down from 9.1% in 2018.
The methodology tracks four major material categories: metals, non-metallic minerals (sand, gravel, limestone, cement), fossil fuels, and biomass. Each category is tracked through extraction, processing, use, and end-of-life. The analysis reveals a stark distribution: metals have the highest circularity rate (close to 50% for some metals like aluminium and copper), while non-metallic minerals, which form the bulk of material consumption globally due to construction, have rates close to zero.
Four Major Material Categories
| Category | Share of Global Material Use | Circularity Challenges | Circular Strategies |
|---|---|---|---|
| Non-metallic minerals | ~50% (dominated by construction) | Low density; high volume; difficult to sort and transport economically | Design for deconstruction; aggregate recycling; industrial symbiosis (fly ash in concrete) |
| Biomass | ~25% (food, fibres, timber) | Food waste; contaminated organic streams; land competition | Regenerative agriculture; bio-waste composting; cascading use of wood |
| Fossil fuels | ~15% (energy) | Combustion means irreversible loss from material cycle | Renewable energy transition; bio-based material substitution |
| Metals | ~10% (highest circularity potential) | Downcycling; contamination; dissipative uses; complex alloys | Collection infrastructure; hydrometallurgy; design for disassembly of multi-material products |
MFA at the Company Level: Circularity Assessment
MFA is not only a macroeconomic tool. Companies increasingly conduct material flow analyses of their own operations and supply chains to identify where material value is lost, where circular strategies can be deployed most effectively, and how to measure progress over time.
The Ellen MacArthur Foundation developed the Material Circularity Indicator (MCI) as a company-level metric derived from MFA principles. The MCI measures the degree to which material flows through a product lifecycle are circular, on a scale from 0 (fully linear) to 1 (fully circular). It accounts for the share of recycled and renewable inputs, the share of materials that are recovered at end of life, and an adjustment for the useful lifetime of the product relative to industry average.
Example: Urban Mining and the Stock Perspective
One of the most powerful insights from applying MFA to cities is the concept of "urban mining": treating the built environment as a future source of secondary materials. The steel, copper, aluminium, and aggregates locked into buildings and infrastructure represent enormous material stocks that will eventually be released when those structures are demolished. A study of Vienna found that the city's building stock contains more than 300 million tonnes of materials, with steel and concrete dominating. Cities that track these stocks through MFA can plan for future material availability and design demolition policies that ensure high recovery rates when the time comes.
Critical Materials and Supply Chain Risk
MFA reveals not only waste but also strategic vulnerability. Many high-technology products rely on critical raw materials such as lithium, cobalt, neodymium, indium, and gallium, which are produced in highly concentrated geographic locations and have no economic substitutes for specific applications. The EU has designated a Critical Raw Materials list, updated in the Critical Raw Materials Act (2024), of materials where supply concentration combined with high strategic importance creates unacceptable import dependency.
MFA of critical materials reveals how much is currently lost through inefficient end-of-life management. For cobalt, a key component in lithium-ion batteries, global recycling rates remain below 30%. Improving this through better collection, sorting, and hydrometallurgical recovery is both a circular economy priority and a strategic supply security imperative for the clean energy transition.
National governments and international bodies use several standardised MFA-derived indicators to track material use over time:
- Domestic Material Consumption (DMC): Total materials extracted domestically plus imports minus exports. Does not account for materials embedded in imported goods.
- Material Footprint (MF): Total raw material extraction needed to produce all goods consumed in a country, including extraction embodied in imports. A more complete picture of true material responsibility.
- Circularity Rate: As used in the Circularity Gap Report: the share of secondary materials in total material consumption. The headline indicator of actual circular economy progress.
The gap between DMC and Material Footprint is particularly revealing for wealthy countries that have offshored extraction-intensive industries: their DMC appears low, but their MF reveals the full global resource impact of their consumption patterns.
Key Takeaways
- 1Material Flow Analysis (MFA) systematically tracks material inputs, stocks, flows, and outputs through a defined system, providing the diagnostic foundation for circular economy strategy
- 2The Circularity Gap Report uses global MFA to track the Circularity Rate, which fell from 9.1% in 2018 to 7.2% in 2023, reflecting a 21% decline in five years
- 3Four material categories dominate global consumption: non-metallic minerals (50%), biomass (25%), fossil fuels (15%), and metals (10%), each with different circularity challenges
- 4Metals have the highest circularity potential; non-metallic minerals (primarily construction materials) have the lowest, dragging down the global rate
- 5Urban mining views the built environment as a future stock of secondary materials; MFA of city building stocks reveals future material availability
- 6The Material Circularity Indicator (MCI) applies MFA principles at the product level, scoring circularity from 0 (fully linear) to 1 (fully circular)