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How to Calculate a Product Carbon Footprint: Five Steps

How a product carbon footprint is actually calculated under ISO 14067 and the PEF method: declared unit, system boundary, data collection, emission factors, allocation and biogenic carbon - with a worked example, data quality scoring and the fields that belong in the digital product passport.

Author: myDPP Team

How to Calculate a Product Carbon Footprint: Five Steps

A PCF number is easy to state and hard to defend. “2.4 kg CO2e per unit” means nothing on its own: without the system boundary, the data basis and the calculation rules behind it, the figure is neither auditable nor comparable with a competitor’s. That is where most first attempts fail - not on the arithmetic, but on undocumented decisions.

This article walks through the calculation step by step, in the order you actually need it in a project. What a product carbon footprint is, how it differs from a corporate carbon footprint and why it belongs in the digital product passport is covered in our PCF primer. Here we deal with the calculation itself.

Key takeaways

  • A PCF is a life-cycle assessment narrowed to climate impact. The rules sit in ISO 14067:2018, built on ISO 14040 and ISO 14044; the EU’s own alternative is the PEF method under Recommendation (EU) 2021/2279.
  • Three decisions shape the result more than any measurement: the declared or functional unit, the system boundary and the version of the emission factor database. All three have to travel with the number.
  • Offsets must not be subtracted. ISO 14067 requires the footprint to be reported without offsetting; compensation may only be stated separately alongside it.
  • Fossil, biogenic and land-use-change carbon are reported separately. A single aggregate figure without that split does not meet the standard.
  • Two PCF values are comparable only if unit, system boundary, factor source and GWP set match. Moving from IPCC AR5 to AR6 alone changes every result with a methane or nitrous oxide share.
  • The number is now demanded in several places: Article 7 of the Battery Regulation, the environmental performance section of the declaration of performance and conformity under the CPR, the ecodesign parameters of the ESPR - and from 27 September 2026 Directive (EU) 2024/825 limits what you may say about the number in advertising.
  • myDPP does not run life-cycle assessments and does not verify them. We store the number together with its metadata, version it, and serve it through the data carrier.

Which standard applies - and why the choice drives the result

There is no single binding method. There are four frameworks that come up in practice, and the legal act or the customer decides which one governs:

FrameworkPurposeTypical use
ISO 14067:2018carbon footprint of products, quantification and reportinginternational default, B2B evidence
PEF (Recommendation (EU) 2021/2279)16 impact categories, climate change as one of themEU legal acts, PEFCR product categories
GHG Protocol Product Standardproduct-level accountingwidely used internationally, links to Scope 3
EN 15804environmental product declarations (EPD)construction products, CPR

The difference is not academic. PEF mandates company-specific data for many processes where ISO 14067 permits secondary data; PEF handles recycling through the Circular Footprint Formula, while ISO studies usually use the cut-off approach. The same packaging can therefore carry two values differing by more than half - both correct, under different rules.

Practical consequence: fix the framework first, then calculate. When a customer asks for a PCF, ask which standard applies and - if PEF - which PEFCR covers your product category. Where no PEFCR exists, ISO 14067 is the more defensible route.

Step 1: Set the declared unit and the system boundary

Functional or declared unit

A functional unit describes a service: “one year of lighting a 20 m2 room at 500 lux”. A declared unit describes only a quantity: “1 kg of aluminium profile”. For intermediate products whose use the manufacturer does not know, the declared unit is the correct route and is explicitly provided for in ISO 14067.

The most common mistake here is choosing a unit the customer cannot recompute. “Per piece” is only usable if the weight and configuration of the piece are unambiguously defined - otherwise every variant becomes its own figure.

System boundary

The boundary decides which life-cycle stages count:

  • cradle-to-gate - raw material extraction to the factory gate. The normal case for B2B declarations and intermediates.
  • cradle-to-gate plus distribution - often required in retail chains, because transport to the central warehouse falls on the customer.
  • cradle-to-grave - complete, including use and end of life. Mandatory as soon as you make a product claim to consumers.
  • Partial CFP - permitted under ISO 14067 when only some stages are covered, but only under that label.

For products with a use phase, that phase often decides everything. In an electrical appliance running for ten years, most emissions move into use; in packaging, nearly all of it sits in the material. Choosing a boundary that excludes the dominant stage produces a figure that misleads even when the arithmetic is right.

Time reference and representativeness

Fix which financial year the activity data represents, which production site the study covers, and how long the figure is meant to be valid. A PCF without a validity date is worthless within two years - grid mix, suppliers and formulations change.

Step 2: Process map and data collection

Draw the process chain first, then collect data - not the other way round. Without a map, the items nobody owns end up missing: auxiliaries, scrap, internal transport, packaging of intermediates.

For every process on the map you need activity data in physical units:

  • material input per declared unit, including scrap and offcuts (gross input, not the net weight of the product)
  • electricity in kWh, fuels in kWh or m3, steam and compressed air where purchased separately
  • transport work in tonne-kilometres per mode
  • process emissions that do not come from energy - calcination, refrigerant losses, fermentation
  • waste quantities per disposal route

Keep a strict distinction:

  • Primary data - from your meters, your ERP, your suppliers. Mandatory for every process under your own control.
  • Secondary data - from databases. Acceptable for upstream chains you do not influence.

The bridge from bill of materials to calculation is the real project risk here. Pull material quantities automatically from PIM or ERP and the calculation is reproducible; collect them in a spreadsheet and you start from scratch next year.

Electricity: location-based or market-based

Electricity allows two legitimate approaches, and the gap between them is large:

  • location-based - factor of the local grid
  • market-based - factor of the contracted volume, evidenced by guarantees of origin or a PPA

You may calculate both; you must name which one you used. A PCF that shows near-zero electricity emissions on a market basis without citing the instruments will not survive review.

Step 3: Emission factors and GWP values

Every activity datum is multiplied by an emission factor. Two attributes belong to each factor or it cannot be traced: the source and the version.

Common sources:

  • ecoinvent - the broadest LCA database, commercial, versioned
  • EF database (Environmental Footprint) - the reference datasets for the PEF method
  • Sphera / MLC - commercial LCA datasets
  • DEFRA factors - UK government factors, free, strong on transport and fuels
  • ADEME Base Empreinte, ProBas - free, nationally focused

Non-CO2 gases are converted using the IPCC’s GWP100 factors. Under the Sixth Assessment Report (AR6) these include 29.8 for fossil methane and 273 for nitrous oxide; older studies frequently use AR5 (28 and 265). ISO 14067 requires you to state which set was applied. For a product with a material methane share - food, agriculture, waste processes - switching the GWP set alone moves the result by several percent.

Step 4: Allocation, recycling and cut-off

Allocation

When one process yields several products, emissions have to be split. ISO 14044 sets a fixed order:

  1. Avoid allocation - subdivide the process or expand the system boundary
  2. Physical allocation - by mass, energy content or another physical relationship
  3. Other relationships - in practice usually the market value of the co-products

Economic allocation is the last step, not the first - and it makes the result price-dependent. Where main and by-product prices differ sharply, the outcome changes every year; document the price reference date.

Recycling and recycled content

This is where the frameworks diverge most:

  • Cut-off - recyclate enters the system burden-free and no credit is given for supplying scrap. Simple, conservative, usual in ISO studies.
  • Avoided burden - the recycler receives a credit for avoided primary production.
  • Circular Footprint Formula (CFF) - the PEF route, weighting recycled content and recyclability through a market factor.

Recycled content is therefore one of the few levers that lowers the figure immediately - and also one that cannot be checked unless the approach is stated.

Cut-off criteria

ISO 14067 does not require that everything be captured, but that the criteria for omission be declared. Excluding negligible contributions is acceptable; excluding items because the data is inconvenient is not. Keep a list of excluded processes with reasons - it is the first thing a reviewer opens.

Step 5: Biogenic carbon, land use and offsetting

Three items are reported separately and not merged into one total:

  1. Fossil emissions - the core figure.
  2. Biogenic emissions and removals - carbon from biomass. Delayed storage in the product may only be claimed under the conditions of the standard; it does not disappear because it cancels out arithmetically.
  3. Direct land use change (dLUC) - emissions from converting land, typical for agricultural raw materials and relevant to evidence under the EUDR.

Offsetting does not belong in the PCF. The footprint is reported gross; purchased credits may be named alongside, not deducted. From 27 September 2026 Directive (EU) 2024/825 applies as well - it bans, among other things, claiming that a product is climate neutral through offsetting. Anyone advertising a figure should therefore be able to produce the gross number; the details are in our article on the Empowering Consumers Directive.

A worked example

Illustrative, cradle-to-gate, declared unit 1 kg of machined aluminium part, gross input 1.25 kg because of swarf. The factors are orders of magnitude and must be replaced by a named database version in a real study.

ItemActivity dataFactorkg CO2e
Primary aluminium (ingot, EU)1.25 kg8.6 kg CO2e/kg10.75
Electricity, machining (location-based)2.1 kWh0.23 kg CO2e/kWh0.48
Cutting fluid, auxiliaries0.03 kg3.0 kg CO2e/kg0.09
Transport of ingot to plant0.00125 t x 900 km0.08 kg CO2e/tkm0.09
Packaging (cardboard)0.05 kg1.0 kg CO2e/kg0.05
Credit for swarfnot claimed (cut-off)-0.00
Total11.46

Now the same calculation with two changed assumptions - 75 % recycled content in the ingot and market-based renewable electricity:

ItemActivity dataFactorkg CO2e
Aluminium, 75 % recycled1.25 kg2.6 kg CO2e/kg3.25
Electricity, machining (market-based, guarantees of origin)2.1 kWh0.02 kg CO2e/kWh0.04
Remaining itemsas above0.23
Total3.52

Same part, same factory, same standard - 11.46 versus 3.52 kg CO2e. The entire difference sits in two documented decisions. That is precisely why a PCF figure without its metadata is not information, and precisely why the legal acts demand the metadata with it.

Data quality and verification

The PEF method scores data quality on four criteria - technological, geographical and time representativeness plus precision - averaged into a data quality rating; lower is better. Even when calculating under ISO 14067, answer those four questions for each dataset: does the dataset match the technology in use, the region, the period, and how precise is it?

On third-party review:

  • ISO 14067 requires no mandatory external verification, but provides for a critical review under ISO 14044; ISO 14071 describes the procedure.
  • For comparative assertions made to the public, a critical review by a panel is the standard route.
  • EPDs under EN 15804 and ISO 14025 are always externally verified - that is their point.
  • Sector legislation may require its own evidence; the declaration under Article 7 of the Battery Regulation, for instance, hangs on a conformity assessment procedure.

Which EU rules demand a figure - and which method

Legal actWhat is requiredMethod
Battery Regulation (EU) 2023/1542, Article 7carbon footprint declaration per model and per manufacturing plant, in kg CO2e per kWh of total energy over the service life, broken down per Annex II point 4own method in the delegated act; dates nominally 18 February 2025 (EV) and 18 February 2026 (industrial above 2 kWh), coupled to that act
CPR (EU) 2024/3110environmental performance over the life cycle in the declaration of performance and conformity, phased from 8 January 2026calculation with the Commission’s free software
ESPR (EU) 2024/1781carbon and environmental footprint as a possible ecodesign parameter, disclosed in the product passportper delegated act, generally closer to PEF
CBAM (EU) 2023/956embedded emissions per tonne of goodsnot an LCA: installation method under Annex IV, see our CBAM article
ESRS E1 / CSRDScope 1, 2 and 3 at company levelcorporate level; PCF values feed Scope 3 category 1
Directive (EU) 2024/825limits on environmental claims from 27 September 2026not a calculation method but a ban on offset-based neutrality claims

The main lesson from that table: CBAM is not a PCF. Carrying installation values from a CBAM report into a product LCA mixes two incompatible system boundaries.

Five mistakes that make a PCF figure useless

  1. Comparing across different system boundaries. A cradle-to-gate value against a cradle-to-grave value is not a comparison but a category error.
  2. Offsets inside the result. Once credits are deducted, the value is no longer a PCF under ISO 14067.
  3. Company average instead of product data. The corporate carbon footprint divided by unit count is not a PCF; it erases exactly the differences that matter.
  4. Factors without a version. “ecoinvent” is not a source. Without a version number and dataset name the calculation cannot be repeated.
  5. No versioning of your own figure. When a formulation or supplier changes, a new value arises - and the old one must stay traceable, because it is printed on products already shipped.

What of this belongs in the digital product passport

The passport carries not the number alone, but the minimum that makes it checkable:

  • value and unit (e.g. kg CO2e per declared unit; for batteries kg CO2e per kWh)
  • declared or functional unit in plain words
  • system boundary and, if partial, the stages covered
  • standard or method including the PEFCR where applicable
  • emission factor source with version and the GWP set used
  • split into fossil, biogenic and dLUC
  • reference period, site, validity date
  • review status and, where available, a link to the public version of the study

myDPP is not a notified body, not a verifier and not an LCA tool. We do not produce life-cycle assessments. We store these fields as versioned product data, keep track of which version belongs to which batch, and serve them through GS1 Digital Link to whoever scans the data carrier.

Frequently asked questions

Do I need LCA software, or will a spreadsheet do?

For a single product with a manageable bill of materials a spreadsheet is enough, as long as factor source and version are documented. Once several products, variants and annual updates arrive, the spreadsheet becomes the risk - not because of the arithmetic, but because of traceability.

How often does a PCF have to be recalculated?

There is no general deadline. Recalculate when formulation, supplier, site or electricity contract changes - and otherwise review annually, because database versions and grid factors move. Set a validity date instead of waiting for one.

May suppliers provide secondary data?

Yes, for their upstream chains. For processes they operate themselves, primary data is the standard - and that is exactly where a supplier survey pays off. So do not ask for “the CO2 number”, ask for value, system boundary, standard and factor version.

Does renewable electricity with guarantees of origin count?

Market-based yes, location-based no - and both results are legitimate as long as the approach is named. If you publish only the market-based value, be ready to state the location-based one on request.

Can I use my supplier’s CBAM figure as a PCF?

No. CBAM captures embedded emissions per tonne of goods using the installation method of Annex IV, with no life-cycle view. The value may hint at the upstream raw material chain, but it does not replace a dataset under ISO 14067.

Sources

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