The ISO 14067 Process in Practice: How a Product Carbon Footprint is Calculated

You have decided to calculate a product carbon footprint in accordance with ISO 14067. The question now is how the process unfolds and what data is required. This article walks through the calculation step by step, so you understand the sequence of work and where your own resources will be focused.

What ISO 14067 Is and What It Requires

ISO 14067:2018 is the international standard for quantifying and communicating the Product Carbon Footprint (PCF). It builds on the general life cycle assessment standards ISO 14040 and ISO 14044, but restricts the scope to climate impact (GWP).

ISO 14067 requires the following from the calculation:

A clear goal and scope (what the result will be used for).
A functional unit to which the emission is referenced.
A system boundary covering the material life cycle stages.
Data collection with documented quality and representativeness.
Allocation rules applied consistently.
Treatment of biogenic carbon and land use change.
Impact assessment using GWP values (IPCC).
A report enabling reproducibility.

The standard does not require third-party verification, but permits it. Verification increases the credibility of the result.

Step 1: Goal, Scope, and Functional Unit

The first decision in the calculation is what the result will be used for and exactly what is being calculated.

The goal might be, for example: “Provide customer X with the carbon footprint of product Y as an input for Scope 3 calculations” or “Identify the main drivers of product emissions to guide product development.” The goal determines how precise the data needs to be and who will read the result.

The scope defines the boundaries of the product under study: a single product, a product family, or an average across different variants. It includes information about which factory or production process manufactures the product, because the result depends on the place of manufacture.

The functional unit is the unit to which the emission is referenced. A good functional unit describes what the product is used for. Examples:

1 kg of finished product (simple, but not always descriptive).
1 m² of coating over a 50-year service life (accounts for durability).
1 kWh of electricity produced (if it is an energy solution).
1 meal (if comparing the impact of different raw materials).

The functional unit determines half of the calculation choices and comparability. It is worth being careful with it.

Step 2: System Boundary and Cut-Off Rules

The system boundary specifies which life cycle stages are included in the calculation.

Cradle-to-gate covers raw material extraction, transport from suppliers, and manufacturing at the factory. It ends at the factory gate. This is the most common boundary when a customer needs the information for their Scope 3 calculations.

Cradle-to-grave also covers the product’s distribution, use, and end-of-life. It is needed when the goal is to understand the full life cycle impact or to produce the data basis for an EPD.

Cut-off rules specify what may be excluded. ISO 14067 typically allows up to 5% of mass or energy to be excluded, provided that including it would not materially change the result. Excluded items must be documented.

Cut-off rules are not an excuse for laziness: if you suspect that a small material is emissions-intensive (e.g., certain additives or rare metals), it should be included in the calculation even if its mass fraction is small.

Step 3: Data Collection: Primary and Secondary Data

Data collection is almost always the most time-consuming stage. The types of data used:

Primary data is measurement or calculation data specific to the product or process: factory energy consumption, the product recipe (bill of materials), production runs, waste quantities. Primary data should be used as much as possible for the manufacturing stage (gate-to-gate). From suppliers, primary data typically means the emission factor for the raw material as reported by the supplier.

Secondary data is a factor retrieved from databases: the emission factor for electricity in a specific country, average production of a raw material, transport per tonne-kilometre. The most common databases are Ecoinvent, GaBi/Sphera, DEFRA, and sector-specific PEF databases.

Data quality is documented: time period (year), geographic representativeness, technological representativeness, precision. ISO 14067 requires a data quality assessment that identifies where the calculation is weakest.

In practice, the data collection process runs as follows:

The product recipe is confirmed with production.
Energy meters are allocated to the product (if shared across multiple products, allocation is used).
Transport data is collected from the logistics side or from suppliers.
Supplier questionnaires are sent for the most significant raw materials if primary data is desired.
Gaps are filled with secondary data from databases.

Step 4: Allocation, Biogenic Carbon, and Land Use Change

This is where the most common errors occur. Three areas require particular attention.

Allocation. If the same process produces multiple products (e.g., a sawmill yields boards, chips, and sawdust), the emissions must be distributed among them. ISO 14044 and 14067 recommend the following hierarchy:

Avoid allocation by subdividing the process into sub-processes.
Use physical relationships (mass, energy content).
Use other relationships, such as economic value.

The chosen allocation method must be justified and its effect on the result analysed.

Biogenic carbon. Wood-based and biological materials absorb carbon during their growth phase and release it when burned or decomposed. ISO 14067 requires that biogenic carbon be reported separately in the GWP result (“biogenic GWP”). In practice, as a package solution:

Carbon absorbed during biomass growth is counted as negative.
Carbon released at the end of the product’s life cycle is counted as positive.
The net result depends on how long the carbon remains stored in the product.

Land use change. If a raw material originates from an area where land use change has occurred (e.g., deforestation for agricultural use), an emission arises that must be included. ISO 14067 instructs the use of a 20-year amortisation period.

These are the areas where expertise in the calculation distinguishes a good PCF from a vague number.

Step 5: Impact Assessment and GWP Factors

From the inventory data (e.g., kg of methane, kg of N2O, kg of CO2), the impact is calculated using GWP factors.

ISO 14067 recommends GWP100 values (100-year time horizon) from the most recent IPCC reports. In practice, calculations use either IPCC AR5 or IPCC AR6 values. AR6 is the most recent (2021) and is recommended for new calculations, but some databases still use AR5.

Examples of GWP100 values (AR6):

CO2: 1
CH4 (methane, fossil): approximately 30
N2O (nitrous oxide): approximately 273
HFC-134a (refrigerant): approximately 1,530

The standard also permits parallel reporting of GWP20 values, but the primary result is always GWP100.

Step 6: Reporting and Critical Review

ISO 14067 requires that the report documents:

Goal, scope, functional unit, system boundary.
Inventory data and its sources.
Allocation choices and justifications.
Treatment of biogenic carbon.
Impact assessment results (kg CO2-eq per functional unit).
Data quality assessment.
Sensitivity analysis, where relevant.
Interpretation: what drives the emissions, where there is uncertainty.

Critical review is a review procedure under ISO 14040/14044 that is recommended when the result is used publicly or when comparability is important. ISO 14067 requires a critical review if the result is communicated publicly and contains comparative assertions.

External verification is not a mandatory requirement of ISO 14067, but is common practice and a requirement when a client (e.g., a Scope 3 calculation commissioner) demands it. NGS offers verification as part of a calculation project or separately for an existing calculation: Verification service.

Frequently Asked Questions

What is ISO 14067?

ISO 14067 is the international standard for calculating and communicating a Product Carbon Footprint (PCF). It builds on the general LCA standards ISO 14040 and 14044, but restricts the scope to climate impact.

What is a functional unit and why does it matter?

A functional unit is the unit to which the emission is referenced (e.g., 1 m² over a 50-year service life). It defines what is being calculated and what the product is compared against. A good functional unit describes the function provided by the product, not merely a quantity.

What do cut-off rules mean?

Cut-off rules are the rules for what may be excluded from the calculation. ISO 14067 typically permits the exclusion of small material or energy flows if their effect on the result is minor. Excluded items are documented.

How is biogenic carbon handled?

Biogenic carbon (wood-based, biological) is reported separately in the GWP result. Carbon uptake during the growth phase is counted as negative and release at end of life as positive. The net impact depends on how long the carbon remains stored in the product.

What GWP factors are used?

GWP100 values from the most recent IPCC report. For new calculations, AR6 (2021) is recommended, but some databases still use AR5. The source of the factors used is documented in the report.

Does ISO 14067 require external verification?

Not as a mandatory requirement. The standard requires a critical review if the result is communicated publicly and contains comparative assertions. External verification is required in practice most often by the client or regulation, not by the standard itself.

Need a carbon footprint for your product?

We manage the ISO 14067 process from start to finish: data collection, calculation, report, and verification where needed. The bulk of the work (coordination and the calculation itself) is handled by us; from you we need access to production and supplier data and a person familiar with the product’s manufacturing.

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