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EPD inputs onlyA1–A3 GWP-total

Sum EPD carbon

For each product, enter the project quantity expressed in that EPD's declared unit and its A1–A3 GWP-total value per declared unit. The worksheet returns transparent multiplication and a subtotal.

Who it's for: sustainability consultants and architects summing declared EPD carbon figures at construction documents.

Product 1
Product 2
Product 3

How to use this calculator

1
Verify each EPD
Confirm the declaration is applicable, valid, independently verified where required, and reports the intended GWP indicator and A1–A3 scope.
2
Match the declared unit
Convert the project quantity into the exact declared unit used by that EPD. Do not treat one kg, m², m³, item, or functional unit as interchangeable.
3
Enter the published value
Copy the A1–A3 GWP-total value per declared unit; retain the EPD identifier in project records.
4
Review the subtotal
The worksheet multiplies each entered quantity by its matching factor and sums kg CO₂e. Interpret comparisons and building-level scope separately.

The formula

Subtotal = Σ(quantity in EPD declared units × A1–A3 GWP-total per declared unit).

Worked example

Example
20 declared units × 4.5 kg CO₂e/unit plus 3 declared units × 12 kg CO₂e/unit = 126 kg CO₂e for the entered A1–A3 rows.

When this estimate will be off

  • No generic factors, ICE values, densities, waste rates, replacements, service lives, transport, construction, use, end-of-life, or Module D values are supplied.
  • A mathematical subtotal does not make EPDs comparable. PCR, standard version, declared/functional unit, geography, technology, data quality, validity, modules, scenarios, and indicators must be reviewed.
  • This is not a whole-building LCA, procurement recommendation, certification assessment, or environmental claim.
  • Negative published values are preserved for transparent arithmetic; their accounting and interpretation must be checked in the source declaration and applicable method.

Frequently asked questions

A common mistake: No generic factors, ICE values, densities, waste rates, replacements, service lives, transport, construction, use, end-of-life, or Module D values are supplied.

They lacked row-level dataset version, geography, declared-unit, licensing, and provenance metadata. A named material is not enough to select a defensible product value.

Not from this arithmetic alone. First establish aligned system boundaries, quantities, EPD/PCR basis, building scope, service life, scenarios, and data-quality rules.

Sources

  • ISO 14025:2026 — Current principles and requirements for EPD programmes and declarations
  • ISO 21930:2017 — Core rules for construction-product and service EPDs

Sources and review record

Sources and method basis

  • ISO 14025:2026 environmental product declaration principles and requirements
  • ISO 21930:2017 core rules for construction-product and service EPDs
  • https://www.iso.org/standards.html

Limitations

  • Multiplies only user-supplied quantities in matching declared units by user-supplied A1-A3 GWP-total values; it does not supply factors, establish comparability, or perform whole-building LCA or certification.

This free Embodied Carbon by Material Calculator is built and maintained by DataDrivenAEC, using the relevant codes and standards. It does not substitute for professional judgment.