15 September 2026

How to Model Recycled Content in Your Product LCA

Model recycled content by splitting the product’s material quantity between virgin and secondary-material inputs—not by reducing the final carbon result by the recycled-content percentage. The allocation method, dataset boundaries, recycling losses, downstream processing, and supplier evidence all affect the result.

TL;DR

Start with the governing PCR, Product Environmental Footprint rule, database system model, or customer requirement. Split the BOM mass into separate virgin and recycled inputs, add any collection and reprocessing stages missing from the datasets, account for losses, and keep end-of-life recycling separate from recycled content entering the product.

1. Choose the allocation method first

The appropriate recycling-allocation approach depends on the study goal and applicable methodological rules; no method is universally best for every application. The choice can materially change the LCA result and whether the model rewards recycled inputs or end-of-life recyclability, according to the Swedish Life Cycle Center’s recycling overview.

Process from governing method selection through BOM splitting, dataset boundary checks, recycling losses, downstream conversion, and end-of-life review

Check requirements in this order:

Governing PCR or sector rule.
Required method, such as the EU Product Environmental Footprint method.
Database system model.
Customer or program requirement.
Documented study goal and scope when no method is prescribed.

For ecoinvent data, select a system model consistent with the study goal and scope. Ecoinvent identifies four models: Allocation, cut-off by classification; Allocation, cut-off, EN15804; Allocation at the point of substitution; and Substitution, consequential, long-term. Mixing datasets from different system models can introduce inconsistent allocation assumptions, as explained in the ecoinvent system-model guidance.

Common recycling-allocation approaches

Approach	Common shorthand	Treatment described in the source
Recycled content or cut-off	100:0	Virgin-production burdens stay with the first product system; the secondary-material user carries the burdens of making recovered material usable.
Shared allocation	50:50	Recycling burdens or benefits may be split between product systems.
Avoided burden or end of life	0:100	Recycling benefits are assigned primarily to the product supplying recyclable material at end of life.
Circular Footprint Formula	Prescribed formula with multiple variables	Addresses recycled inputs, end-of-life recovery, material quality, allocation, and substitution under the EU Product Environmental Footprint method.

The 100:0, 50:50, and 0:100 descriptions come from the EcoMatters recycling-allocation comparison. The Circular Footprint Formula is a prescribed method, not a generic recycling credit that can be inserted into any LCA, according to the EU Product Environmental Footprint annexes.

Comparison of 100:0 recycled-content allocation, 50:50 shared allocation, and 0:100 avoided-burden allocation

2. Split the BOM quantity into virgin and recycled inputs

Create separate inventory lines for the virgin and recycled shares. Apply the recycled-content percentage to the underlying material quantity rather than treating it as a percentage reduction in the product’s final carbon result. This separate-input pattern is documented in the One Click LCA mixed-material guidance.

For a component with total material mass M and recycled-content share R:

Recycled input = M × R
Virgin input = M − recycled input

A 10 kg component containing 30% recycled material becomes 3 kg of recycled input and 7 kg of virgin input. Those are inventory quantities, not carbon reductions. The two inputs retain the impacts represented by their respective datasets.

A 10 kg component with 30% recycled content is split into 3 kg recycled input and 7 kg virgin input

Keep these fields separate in the BOM or supporting evidence:

Total material mass.
Recycled-content percentage.
Virgin input mass.
Recycled input mass.
Pre-consumer and post-consumer shares where reported.
Material grade and production route.
Supplier and evidence date.

The recycled-content figure describes material entering the current product. It is not the same as the product’s collection rate, recyclability, recycling yield, or end-of-life recycling rate. The latter concerns material potentially recovered after disposal, as the Earthster cut-off explanation distinguishes.

3. Check what the recycled-material dataset includes

Under cut-off modeling, secondary material does not inherit the burden of its previous primary production. It still carries relevant impacts from making recovered material usable. “Burden-free at the cut-off point” therefore does not mean zero environmental impact. Recycled paper, for example, can exclude forestry and primary paper production while retaining collection, transport, and recycling impacts, according to the One Click LCA cut-off guidance.

Inspect the dataset documentation to determine whether it already includes:

Collection from the previous user.
Transport to sorting or recycling.
Sorting and separation.
Washing or other preparation.
Reprocessing into usable secondary material.
Yield losses and treatment of rejected material.

Add only the missing processes. Collection, transport, sorting, washing, and related activities must be modeled when they are outside the selected dataset boundary, according to the SimaPro recycling-modeling guidance.

4. Model yield losses explicitly

The quantity of recovered material entering recycling may exceed the usable secondary material delivered to the product system. At a 90% recycling yield, producing 3 kg of usable recyclate requires approximately 3.33 kg of incoming recovered material and produces approximately 0.33 kg of losses. Include treatment of the rejected fraction unless it is already represented in the recycling dataset, following the SimaPro recycling example.

Do not add losses automatically without reading the dataset boundary. If a market or recycling-process dataset already incorporates average sorting efficiency and residual treatment, adding another loss calculation would duplicate those flows.

5. Add downstream conversion separately when needed

Virgin and recycled feedstocks may enter the same manufacturing process after they are combined. Model that conversion separately if it is not included in either material dataset. Rolling, forming, molding, machining, coating, and assembly should not disappear merely because the feedstock contains recycled material.

One published mixed-steel example uses 80% electric-route steel and 20% converter-route steel, followed by a separate hot-rolling process. This illustrates the structure, but production-route datasets are only valid proxies for recycled and virgin content when their material, technology, geography, quality, and allocation assumptions fit the study, as noted in the One Click LCA mixed-steel example.

6. Avoid double counting at end of life

Keep recycled content entering the product separate from recycling after use. Under the cut-off approach, primary-production impacts belong to the virgin-material user, recycling-process impacts belong to the secondary-material user, and unrecycled-waste treatment belongs to the product generating that waste.

If the secondary-material dataset already follows cut-off rules, do not add an avoided-virgin-material credit at end of life unless the governing method explicitly requires it. Combining cut-off datasets with an additional avoided-burden credit can count the recycling effect twice, warns the One Click LCA cut-off documentation. For the wider end-of-life model, follow a consistent approach to model product end of life in LCA.

7. Record evidence and uncertainty

For every virgin or recycled dataset, record the dataset name, version, system model, geography, technology, material grade, recycled-content basis, evidence date, and known gaps. Supplier documentation should state how the percentage was calculated and whether it covers material diverted during manufacturing, material recovered after consumer use, or both. FTC guidance describes recycled content as material recovered or diverted from the waste stream during manufacturing or after consumer use in its report on recycled-content claims.

When supplier-specific data is unavailable, choose a transparent proxy based on material, technology, geography, quality, and allocation compatibility. Document why it was selected and test an alternative dataset where the uncertainty could change the conclusion. Procurement scenarios should change supplier, route, or recycled-content assumptions while holding the allocation method constant; methodological sensitivity should be reported separately.

As products change, preserve these assumptions across BOM versions and variants. Dawn’s assembly source control and product variants keep parts, assemblies, variants, versions, suppliers, and LCA studies together, while its supplier data collection supports mapped requests and supporting evidence. Method selection and review remain human decisions.