ISO 14064-1 vs the GHG Protocol: which one do you need?

Ask three practitioners which standard a corporate carbon footprint should follow and you’ll hear both names. The honest answer is that ISO 14064-1 and the GHG Protocol are not competitors so much as two documents doing different jobs — and most real inventories quietly use both. Here is the difference, without the vendor fog.

Two documents, two jobs

The GHG Protocol Corporate Accounting and Reporting Standard (WRI/WBCSD, free to download) is a methodology: it teaches you how to think about boundaries, scopes 1–3, calculation approaches, and reporting principles. Most of the world’s disclosure programs — CDP, SBTi, the ESRS under CSRD, the SEC and California climate rules — trace their accounting language back to it.

ISO 14064-1:2018 (paid ISO document) is a requirements standard: a list of auditable “shall” statements about what a conforming inventory and report must contain. Its value is the interface it creates with ISO 14064-3, the verification standard — when a tender, a regulator, or a customer asks for “an ISO 14064-1 inventory, third-party verified,” that request is checkable in a way “we followed good practice” is not.

Side-by-side

	ISO 14064-1:2018	GHG Protocol Corporate Standard
Publisher	ISO	WRI + WBCSD
Access	Paid standard	Free PDFs
Nature	Certifiable requirements (“shall”)	Methodology + guidance
Emission structure	Direct (cat. 1) + five indirect categories (2–6)	Scope 1, 2, 3 (15 scope-3 categories)
Verification interface	ISO 14064-3 designed to pair with it	No companion assurance standard
Scope 2 treatment	Category 2; commonly reported dual per GHGP guidance	Explicit location-based + market-based dual reporting
Typical pull	Tenders, certification schemes, regulators in Asia (e.g. Taiwan’s listed-company inventory mandate), supply-chain asks for “verified per ISO”	CDP, SBTi, CSRD/ESRS, most voluntary disclosure

How scopes map to categories

The two structures reconcile cleanly — nothing is lost in either direction:

GHG Protocol	ISO 14064-1:2018
Scope 1	Category 1 (direct)
Scope 2	Category 2 (imported energy)
Scope 3 — transport-related (cat. 4, 6, 7, 9 of the 15)	Category 3 (transportation)
Scope 3 — purchased goods, capital goods, fuel- and energy-related, waste (cat. 1, 2, 3, 5)	Category 4 (products used)
Scope 3 — downstream: use of sold products, end-of-life, leased assets, franchises, investments (cat. 10–15)	Categories 5–6

A well-built data model records each source once and renders it either way — which is exactly how software should treat the two standards (CarbonInk’s report export follows ISO 14064-1 with a scope mapping, for instance).

When ISO 14064-1 is the right frame

• A customer, tender, or certification scheme names ISO 14064-1 — common in East Asian supply chains and public procurement.
• You plan third-party verification and want the inventory built against the same requirements the verifier will test (ISO 14064-3).
• You operate where regulation references ISO — Taiwan’s phased mandatory inventories for listed companies are the loudest current example.

When the GHG Protocol is the right frame

• Your disclosure target is CDP, SBTi, or CSRD/ESRS, whose questionnaires and datapoints speak scope language natively.
• You need the free, detailed calculation guidance — the Scope 2 guidance and the 15-category Scope 3 standard have no ISO equivalent at that level of cookbook detail.
• You’re starting out and want the most widely understood vocabulary for benchmarking against peers.

In practice: use both

The standard pattern for a serious inventory is:

1. Calculate with GHG Protocol methodology — boundaries, scope 2 dual reporting, scope 3 screening across the 15 categories.
2. Structure and state the report per ISO 14064-1 — categories 1–6, significance criteria, uncertainty, the conformity statement.
3. Verify against ISO 14064-3 if anyone downstream needs assurance.

Done this way there is no double work: one dataset, two presentations, and every stakeholder — CDP portal or ISO-quoting procurement officer — gets the shape they asked for. For the full build process, see the step-by-step ISO 14064-1 inventory guide.