One carbon number.
Where does it stop?
A carbon footprint is Global Warming Potential in kilograms of CO2e — one climate number, pulled from a life cycle with dozens of stages. A carbon rate is that same number divided by a declared unit. Neither means anything until you know exactly which stages it covers — which is what the rest of this page measures.
The scale this page measures
Every carbon claim covers some portion of this tape. Scroll to see exactly what “partial” and “full” coverage look like side by side.
Jump to the ruler ↓01 · The Scale
Before the number, the boundary
Every EPD, footprint, or “carbon rate” you will ever be shown is built on the same underlying scale — five life-cycle stages defined by EN 15804+A2, running from raw materials through to whatever happens after the product’s working life ends. The number changes depending on how much of this tape was actually measured.
This is the full tape. On its own, a carbon figure says nothing about how much of it was actually measured — that has to be stated separately, as a boundary declaration. Module-by-module detail for every stage (down to A1, A2, A3, B1–B7, and D1–D4) lives on our Life Cycle Assessment page.
02 · Three Terms, Not One
Footprint, rate, and full EPD are not interchangeable
All three get called “carbon numbers” in conversation. Only one of them is defined by an ISO standard.
Read across each row: what the term actually reports, what it demands of its boundary, and which standard — if any — governs it.
| Term | What it reports | Boundary requirement | Governed by |
|---|---|---|---|
| Carbon footprint | Global Warming Potential, in kg CO2e — one climate-impact indicator. | Any declared scope, but the modules covered must be stated alongside the number. | ISO 14067 · PAS 2050 · GHG Protocol |
| Carbon rate Informal term | The footprint above, divided by a declared or functional unit — e.g. [X] kg CO2e ÷ [Y] unit. | Inherited entirely from the footprint it’s built on — same modules, same caveats. | Not an official standard term — a presentation convention only. |
| Full LCA / EPD | GWP plus acidification, eutrophication, resource depletion, water use, waste, land use, and more. | Cradle-to-gate, cradle-to-grave, or with-module-D — set by the product’s PCR. | ISO 14040/44 · ISO 14025 · EN 15804+A2 |
03 · Before You Compare Two Numbers
Six questions to ask before comparing any two carbon rates
A lower rate isn’t automatically a better product — it might just be measuring less of the life cycle. Check these six things before putting two numbers side by side.
Any single mismatch below is enough to make two “carbon rates” unsafe to compare directly — even when both look like the same kind of number.
- Same declared or functional unit on both sides?
- Same Product Category Rules (PCR)?
- Same module boundary — gate, grave, or +D?
- Third-party verified under ISO 14025?
- Full CFP, or partial (cradle-to-gate only)?
- Offsets kept separate, or folded into the number?
04 · Partial Coverage
A1–A3 only? That’s a partial CFP — not a footprint claim
Under ISO 14067, a full Carbon Footprint of a Product (CFP) claim requires cradle-to-grave coverage. A result built only from A1–A3 — raw materials, transport, manufacturing — is real, usable data. But it is a partial CFP, and must be labelled as one. A “carbon rate” calculated from A1–A3 alone describes production only — not the product’s life.
Partial CFP — cradle-to-gate only. Not a complete carbon-footprint-of-product claim under ISO 14067, and any “carbon rate” derived from it should say so plainly.
05 · Full Coverage
Cradle-to-grave is the compliant claim — and where an EPD Climate Declaration comes from
Extend the same tape through construction (A4–A5), use (B1–B7), and end of life (C1–C4) and the result becomes a full cradle-to-grave CFP — the coverage ISO 14067 requires for an unqualified footprint claim. Module D (reuse, recovery, recycling) sits beyond the product’s own system boundary, so it’s always reported as a separate, optional figure.
An EPD Climate Declaration is simply this same result, extracted as a single-issue summary from a complete, third-party-verified EPD. It follows the same ISO 14025 rules as the full document — it is not a shortcut, a standalone product, or a lighter-touch alternative.
06 · Inside the Number
GWP itself isn’t one number either
Even within a single climate-change result, GPI 5 / EN 15804+A2 requires four sub-indicators to be tracked and reported separately — a headline “kg CO2e” is only the GWP–total line, and the declaration must show the fossil, biogenic, and land-use splits behind it, not just the sum.
GWP–total
All greenhouse-gas contributions combined into one CO2e figure.
GWP–fossil
Emissions from fossil-fuel sources only.
GWP–biogenic
Carbon uptake and release associated with biological (plant-based) material.
GWP–luluc
Emissions from land use and land-use change.
07 · Two Rulebooks, Two Numbers
Biogenic carbon: included by some methods, excluded by others
An EPD Climate Declaration excludes biogenic CO2 and carbon storage from its headline result. ISO 14067, PAS 2050, and the GHG Protocol include it. Two “[X] kg CO2e per declared unit” figures built on different methods are not directly comparable — even when the unit and the module boundary match exactly.
The highlighted modules below mark where biogenic accounting diverges: uptake during use, release and storage credit at end of life and beyond — the exact stages an EPD Climate Declaration reports differently from an ISO 14067 / PAS 2050 / GHG Protocol result.
Offsets are not part of the number. Carbon credits, purchased removals, and other offset mechanisms are explicitly excluded from the assessed footprint indicators under ISO 14067 and EPD rules. They may be disclosed as separate “additional environmental information” alongside a declaration — never folded into the reported kg CO2e.
Ready to measure the whole tape — not just one stage of it?
A carbon rate is one useful cross-section. A full Life Cycle Assessment covers every stage and every indicator category, and an independent verification confirms both.