Knowledge base

ISO 14064-1:2018 – Requirements in Simple Language

This guide explains what ISO 14064-1:2018 requires, clause by clause, and what an auditor may ask you to show as evidence.

Prem Kumar Dvivedi · 12 tháng 9, 2026

 It covers 68 requirements across 7 main areas. This is not simply a checklist. A checklist only asks, “Do you have this?” This guide explains what you need to have and what evidence can demonstrate that you have actually implemented it.

If you first want to understand your current position, you can use an ISO 14064-1:2018 readiness assessment to identify gaps and measure your level of preparedness.

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4. Five Principles of a Good GHG Inventory

Clause 4

Your greenhouse gas (GHG) inventory should follow these principles:

Relevant

Include information that is important and useful to the people who will use the inventory.

Evidence: Your inventory methodology should explain how you decided what information was relevant.

Complete

Include all relevant emission sources within your defined boundary. If something is excluded, explain why.

Evidence: Completeness checks and a list of excluded sources with reasons.

Consistent

Use the same boundaries and calculation methods from year to year so that results can be compared.

Evidence: Records showing consistency. If something changes, explain the change and recalculate previous figures where necessary.

Accurate

Make the figures as accurate as reasonably possible and reduce errors or bias.

Evidence: Records of accuracy checks and identification of estimated data.

Transparent

Someone else should be able to understand what you did, how you calculated the figures and why you made your decisions.

Evidence: Clearly documented methodology that another person could follow.

Where two principles conflict, such as completeness and accuracy, you should record the decision you made and why.

Evidence: Records explaining important decisions and judgements.

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5. Defining the Organizational and Operational Boundary

Clauses 5.1 and 5.2

You must clearly define what is included in your GHG inventory.

Consolidation approach

Choose and document how you will consolidate emissions:

• Operational control

• Financial control

• Equity share

Evidence: The selected approach and the reason for choosing it.

Organizations, sites and assets

Identify all relevant:

• Companies and subsidiaries

• Sites and facilities

• Joint ventures

• Leased assets

• Other relevant entities

Clearly state what is included and excluded.

Evidence: Consolidation list, organization chart or legal structure diagram.

Acquisitions and disposals

If you bought or sold a company, facility or asset during the reporting year, explain how it was treated.

Evidence: Records showing the acquisition or disposal, including dates.

Category 1 – Direct emissions

Identify emissions that come directly from sources you own or control, such as:

• Fuel burned at your facilities

• Company-owned vehicles

• Process emissions

• Refrigerant leakage

• Fugitive emissions

Evidence: List and calculation of Category 1 sources.

Category 2 – Purchased energy

Identify emissions associated with energy you purchase, such as:

• Electricity

• Heat

• Steam

• Cooling

Evidence: Electricity and energy consumption records and related calculations.

Category 3 – Transportation

Consider emissions from transportation activities, such as:

• Business travel

• Employee commuting

• Upstream transportation

• Downstream transportation and distribution

Evidence: Travel records, commuting information and transportation data.

Category 4 – Purchased products and services

Consider emissions connected with what your organization purchases, including:

• Purchased goods and services

• Capital goods

• Waste

• Other upstream activities

Evidence: Procurement, supplier, waste and related activity data.

Category 5 – Products after sale

Consider emissions that occur after your products or services leave your organization, such as:

• Use of sold products

• End-of-life treatment

• Downstream leased assets

• Franchises

Evidence: Relevant downstream activity data and calculations.

Category 6 – Other indirect emissions

Consider other indirect emission sources that do not fall under the previous categories, such as certain investments.

Evidence: Assessment of other possible indirect sources.

Consider all six categories

You should consider all six categories, even if you decide that some are not relevant to your organization.

Evidence: A documented review of each category and the conclusion reached.

Significant indirect emissions

You must define how you decide which indirect emissions are significant.

Consider factors such as:

• Size of emissions

• Your level of influence

• Risks and opportunities

• Industry guidance

• Outsourcing

• Stakeholder interest

Evidence: Documented significance criteria and evidence that they were applied consistently.

Exclusions

Every excluded source should be listed with a reason.

Evidence: An exclusions register showing:

• What was excluded

• Why it was excluded

• Any threshold used

• The basis for the threshold

Direct emission sources should not simply be ignored.

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6. Calculating the GHG Emissions

Clauses 6.2 to 6.8

Identify all sources

List all relevant:

• Emission sources

• Sinks

• Carbon reservoirs

within your defined boundary.

Evidence: Inventory by site, activity and category, supported by process or facility diagrams where appropriate.

Review the inventory every year

Do not simply copy last year's list. Review it for the current reporting period.

Evidence: Dated evidence showing that the inventory was reviewed.

Choose a calculation method

For every source, decide whether emissions will be calculated using:

• Calculation

• Measurement

• A combination of both

Document the reason for your choice.

Evidence: Quantification method and justification for each source.

Estimation and modelling

If you estimate or model data, document how you did it.

Evidence: Documented estimation or modelling method.

Activity data collection

Have a clear process explaining:

• What data is required

• Where it comes from

• How often it is collected

• Who is responsible for it

Evidence: Data collection procedure with the source and responsible person identified.

Complete activity data

Make sure your data covers the full reporting period.

Examples of evidence include:

• Electricity bills

• Meter readings

• Fuel purchase records

• Vehicle mileage

• Waste records

• Refrigerant service records

• Procurement records

• Travel records

Where possible, compare the data with financial or operational records.

Estimated data

If any data has been estimated, clearly identify it.

Evidence: Estimated data clearly marked in working papers and disclosed in the report.

Emission factors

Record every emission factor used and its source.

Evidence: Emission factor register showing:

• Factor used

• Source

• Publication year

• Version

Global Warming Potentials (GWPs)

Record the GWP values used and identify the relevant IPCC report.

Evidence: Named GWP dataset and source.

Review emission factors

Review and update emission factors regularly, normally as part of the annual inventory review.

Evidence: Annual review records. If you developed your own factor, document the reason and method.

Greenhouse gases

Include all relevant greenhouse gases, including refrigerants.

Evidence: List of gases included and explanation for any gases excluded.

Reproducible calculations

Another person should be able to start with the original data and reproduce the final reported emissions.

For example:

Invoice → Activity Data → Emission Factor → Calculation → Tonnes CO₂e

Evidence: Calculation spreadsheets or software showing:

• Formulas

• Unit conversions

• Source data

• Final calculations

Independent calculation check

Someone other than the person who prepared the calculation should review it.

Evidence: Review record showing the reviewer's name and date, along with appropriate version control.

Base year

Select a base year and document why it was selected.

Evidence: Base year and documented justification.

Base year consistency

The base year should be calculated using the same basic approach as the current year's inventory, with supporting evidence retained.

Evidence: Base-year inventory and underlying data.

Base year recalculation rules

Define when the base year must be recalculated.

Possible triggers include:

• Acquisition

• Disposal

• Outsourcing

• Change in boundary

• Change in calculation method

• Change in emission factor

• Discovery of a significant error

Define the significance threshold where appropriate.

Evidence: Documented base-year recalculation policy.

Apply recalculation rules

When a trigger occurs, apply the policy and disclose the recalculation.

Evidence: Before-and-after figures and recalculation records.

Uncertainty

Assess how certain or uncertain your emission figures are.

Evidence: Uncertainty assessment covering data and calculation/model uncertainty.

Major sources of uncertainty

Identify which sources create the greatest uncertainty.

Evidence: List of major uncertainty sources and evidence that this information is being used to improve future data quality.

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7. Emission Reductions, Offsets and Removals

Clause 7

Reduction projects

Record any projects or actions that reduce emissions and calculate their impact separately.

Evidence: Reduction/mitigation action register showing:

• Action

• Period

• Boundary

• Calculation method

Avoid double counting

Make sure a reported reduction is actually a reduction and not simply the result of producing less, travelling less or having lower activity.

Evidence: Records showing how the reduction was separated from normal changes in activity.

Offsets and credits

If you purchase carbon credits or offsets, document them properly and show that they have been retired.

Evidence: Details such as:

• Credit/instrument type

• Vintage

• Registry

• Retirement evidence

Report emissions and offsets separately

Do not combine offsets with emissions to show only a single "net" number.

Evidence: Report showing gross emissions and offsets separately.

Removals and carbon storage

If you claim carbon removals or storage, document the calculation method and consider the risk that the stored carbon could later be released.

Evidence: Removal calculation method, monitoring information and treatment of reversal risk. If not applicable, state why.

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8. Managing GHG Inventory Information

Clauses 8.1 and 8.2

Inventory management procedure

Have a documented process for managing the inventory and clearly identify responsibilities.

Evidence: Procedure identifying:

• Data owners

• Inventory preparer

• Reviewer/approver

Competence

People preparing the inventory must have suitable knowledge, training or experience.

Evidence: Training records, qualifications and experience.

System should not depend on one person

Ask:

"If the person currently preparing the inventory leaves tomorrow, could someone else take over?"

The system should contain enough information for another competent person to continue the work.

Evidence: Clear procedures, records and documentation.

Accountability

A responsible person should be formally accountable for the inventory and have enough authority to obtain the necessary resources.

Evidence: Named accountable person and documented reporting route to senior management/leadership.

Review and approval

The inventory should be reviewed and approved before it is published.

Evidence: Signed or electronically approved record showing the date of approval.

Quality checks

Define what checks must be completed before reporting the figures and who performs them.

Possible checks include:

• Completeness checks

• Year-on-year comparison

• Explanation of major changes

• Second-person review

• Error correction records

Evidence: Quality-control records showing the reviewer and date.

Record retention

Define what information must be retained and for how long.

This may include:

• Activity data

• Emission factors

• Calculations

• Assumptions

• Reports

• Supporting evidence

Evidence: Documented retention schedule.

Base year records

Keep supporting evidence for the base year for as long as the base year remains relevant.

Evidence: Records retained for the required period.

Retrieval of old records

You should be able to retrieve evidence from previous reporting periods when required.

Evidence: Appropriate storage, access controls, backups and evidence that records can actually be retrieved.

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9. Reporting the GHG Inventory

Clauses 9.2 and 9.3

Reporting plan

Before preparing the report, define:

• Who will use the report

• Purpose of the report

• Reporting period

• Whether verification will be carried out

Evidence: Reporting plan or agreed terms of reference.

Report boundaries

The report must clearly state:

• Organizational/operational boundaries

• Consolidation approach

Direct emissions and removals

Report the total direct emissions and removals.

Evidence: Category 1 total.

Indirect emissions

Report indirect emissions separately by category rather than combining everything into one number.

Evidence: Individual category totals.

Methodology

The report should state:

• Reporting period

• Calculation methods

• Emission factors

• Global warming potentials

Evidence: Methodology section of the report.

Exclusions

List excluded sources and explain why they were excluded.

Evidence: Exclusions disclosed in the report itself.

Base year comparison

Report the selected base year and compare current results with it.

If the base year was recalculated, disclose the recalculation.

Uncertainty

State the level or assessment of uncertainty associated with the inventory.

ISO 14064-1 conformity

The report should clearly state that it was prepared in accordance with ISO 14064-1.

Biogenic CO₂

Report biogenic CO₂ emissions separately from fossil-fuel-related CO₂ emissions.

Market-based electricity

If purchased electricity is reported using a market-based method, also report the location-based figure where applicable.

Evidence: Both figures and supporting contracts, certificates or other relevant evidence.

Year-to-year comparison

The figures should be comparable between reporting years.

Any changes in:

• Method

• Boundary

• Emission factor

• Activity

• Organizational structure

should be explained.

Evidence: Multi-year comparison table, change log and restated figures where necessary.

The report should make it clear whether a reduction is a genuine emissions reduction or simply the result of a change in activity, boundary or calculation method.

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10. Verification of the GHG Inventory

Clause 10

If the inventory is going to be verified:

Agree verification requirements

Agree with the verifier on:

• Level of assurance

• Materiality

• Verification criteria

Evidence: Verification engagement terms. If verification is not required, document that decision and its reason.

Competent and independent verifier

The verifier should be appropriately accredited and independent.

Evidence: Relevant accreditation, including ISO 14065 where applicable, and evidence of independence.

Prepare the evidence package

Prepare all information the verifier may need in an organized manner.

Evidence: Indexed evidence file linked to the relevant sections of the GHG report.

Provide access

The verifier should have access to the necessary:

• Sites

• Systems

• Documents

• Personnel

Evidence: Agreed access arrangements.

Previous verification findings

Review findings from the previous verification and confirm that they have been addressed.

Evidence: Previous verification statement, findings and evidence showing how each finding was closed.

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How to Use This Guide

The purpose of ISO 14064-1 is not to create a large collection of manuals, templates and files just for the sake of documentation.

The standard is mainly looking for evidence that important decisions have been:

• Properly considered

• Clearly documented

• Implemented

• Supported by evidence

In many cases, this is a much smaller task than organizations initially expect.

Documentation alone is not compliance

Having a long procedure does not automatically mean you are compliant.

In fact, a procedure that nobody follows can create a bigger problem because an auditor may find a difference between what your procedure says and what your organization does.

The real test is simple:

Can the person responsible for the work recognize their actual activities in the documented system?

Your documentation should reflect what your organization really does, how it collects and calculates its GHG data, how it checks the information, and how it reports the results.

In short: ISO 14064-1:2018 is not about creating paperwork. It is about having a reliable, transparent and traceable GHG inventory that can be supported with evidence.


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