Standards and reporting
Carbon accounting
Carbon accounting turns defined activities into a greenhouse-gas inventory through documented boundaries, methods and evidence rather than a single unexplained footprint total Corporate Standard.
What is carbon accounting measuring?
A corporate inventory accounts for greenhouse gases associated with a defined organisation and period, rather than the footprint of one product Corporate Standard Corporate versus product accounting.
Module 01 / 04
Purpose
Name the management decision or reporting output the inventory must support.
Module 02 / 04
Period
Choose an activity period and record how partial-period evidence is handled.
Module 03 / 04
Boundary
Identify the operations and activities before calculating their emissions.
Module 04 / 04
Recipient
Explain the accounting basis to whoever receives the result.
Read the detailed guidance and evidence
The GHG Protocol guide explains the standards themselves, while this guide develops the practical inventory process.
What belongs in the opening brief?
This original brief makes the accounting assignment reviewable before collection starts.
| Record or decision | What to preserve | Why it matters |
|---|---|---|
| Reporting unit | Named entities, sites and financial or operational perimeter | Avoid an undefined group footprint. |
| Time coverage | Start/end dates and treatment of opening or closing sites | Prevent gaps hidden by invoice dates. |
| Method basis | Standard, consolidation approach and named reviewer | Allow the decisions to be challenged. |
| Deliverables | Working data, methods, issues and labelled totals | Specify more than a dashboard screenshot. |
How should the source population be built?
Create a complete activity population using the selected organisational and operational boundaries before asking for a factor Chapters 3, 4 and 6.
Module 01 / 04
Operations
Reconcile the site list to the operational and entity records.
Module 02 / 04
Energy
Identify fuel and purchased-energy streams separately.
Module 03 / 04
Value chain
Screen relevant upstream and downstream activities using the applicable standard.
Module 04 / 04
Completeness
Retain a reason for each exclusion or unresolved source.
Read the detailed guidance and evidence
The Scope 1 guide identifies direct sources, while Scope 2 explains purchased energy.
Value-chain work needs category-specific methods rather than a universal spend multiplier Calculation guidance.
What should one activity record contain?
This editorial record design keeps a reported amount connected to its evidence.
| Record or decision | What to preserve | Why it matters |
|---|---|---|
| Record identity | Stable ID, entity, site, activity and period | Make duplicated or replaced records identifiable. |
| Original evidence | Document reference, owner, quantity and original unit | Allow the preparer to return to the source. |
| Transformation | Allocation, conversion, factor row and assumptions | Expose the steps between activity and tonnes. |
| Quality status | Actual, estimated, missing, corrected or excluded with reason | Keep uncertainty separate from a measured zero. |
Read the detailed guidance and evidence
A missing invoice is an open collection issue rather than evidence that no activity occurred.
The ESG data collection guide develops ownership and approval fields.
How are methods and factors selected?
Match the factor to the activity, unit, geography and activity year, then retain its publication version 2026 set Methodology.
Module 01 / 04
Activity
Distinguish energy consumption, distance, mass and expenditure.
Module 02 / 04
Unit
Show that the quantity unit matches the factor denominator.
Module 03 / 04
Coverage
Identify direct, upstream or other components in the factor.
Module 04 / 04
Version
Keep the row and update used, not merely the department name.
Read the detailed guidance and evidence
DESNZ’s annual activity factors and Defra’s spend-based multipliers are different publications intended for different inputs Activity versus expenditure.
For Scope 3, the method may differ between activities in the same category, so a category label alone is insufficient Method selection.
GHG Protocol tools can support calculations, but using those particular spreadsheets is not mandatory Tools and guidance Tool-use FAQ.
How could a fictional first inventory be organised?
This invented maintenance business separates evidence problems before producing totals.
| Record or decision | What to preserve | Why it matters |
|---|---|---|
| Workshop gas | Twelve consumption periods, supplier kWh and a boundary owner | Check the energy basis before selecting a fuel factor. |
| Service vehicles | Fuel transactions reconciled to the controlled-vehicle list | Remove duplicate imports while retaining the correction trail. |
| Purchased electricity | Meter quantities with separately labelled accounting method | Do not mix purchased energy into direct fuel emissions Purchased-energy accounting. |
| Supplier freight | Shipment evidence and an explicitly chosen category method | Develop the value-chain estimate separately. |
Read the detailed guidance and evidence
The business initially finds a duplicated vehicle file and one missing gas period, so it resolves those records before describing the inventory as complete.
What should happen when data is missing?
Use transparent estimation and quality controls rather than treating unavailable information as zero Chapter 7 July correction notice.
Module 01 / 04
Cause
Describe whether the gap is missing activity, missing factor or unresolved boundary.
Module 02 / 04
Method
Explain the estimate and the evidence used to construct it.
Module 03 / 04
Owner
Name the person expected to resolve or review the gap.
Module 04 / 04
Consequence
Identify the totals and outputs affected by a later correction.
Read the detailed guidance and evidence
The July 2026 flat-file correction replaced some incorrectly reported zero factors with blanks where data were unavailable Correction notice.
That distinction matters in a calculation system because a zero can suppress a result while a missing input should remain visible.
In the fictional case, the preparer labels the estimated gas period and gives the reviewer both its working and replacement plan.
Which checks should the reviewer perform?
Use these original tests to inspect the calculation rather than accepting the aggregate on trust.
| Record or decision | What to preserve | Why it matters |
|---|---|---|
| Population check | Compare expected activities with received records | Identify an absent source before reviewing decimal places. |
| Reproduction check | Recalculate selected source records independently | Test factor, unit and arithmetic together. |
| Overlap check | Inspect fuel, purchased energy and upstream components | Avoid adding the same emissions component twice. |
| Change check | Explain variations by activity, method, boundary and correction | Avoid describing every lower total as operational progress. |
How should year-on-year changes be explained?
Apply a documented base-year recalculation policy and distinguish structural or method changes from organic growth or decline Chapter 5.
Module 01 / 04
Activity
Identify genuine changes in production, travel or energy use.
Module 02 / 04
Factor
Explain a changed factor or its underlying methodology.
Module 03 / 04
Structure
Review acquisitions, disposals and changed boundary facts.
Module 04 / 04
Correction
Retain the original error and the reason for replacement.
Read the detailed guidance and evidence
The Corporate Standard requires a company-set significance threshold and recalculation policy rather than one universal percentage for every inventory Base-year policy.
A factor update can change the result without proving that a company consumed less energy.
Present the numerical movement with its cause and do not quietly overwrite previously approved working files.
What should a complete handover contain?
A usable handover lets a different preparer reproduce and continue the inventory.
| Record or decision | What to preserve | Why it matters |
|---|---|---|
| Boundary and method memo | Chosen approaches, exclusions and judgement owners | Explain what the total represents. |
| Calculation export | Source IDs, activity, factors, transformations and results | Make the inventory usable outside its platform. |
| Issue register | Estimates, unresolved questions and review decisions | Show the limits of the current result. |
| Output map | Which totals feed each recipient’s specific request | Prevent an inventory being mistaken for every reporting obligation. |
What if a recipient asks for a different footprint?
Corporate and product inventories answer different questions, so confirm the requested accounting unit before reusing a total Corporate and product standards.
Module 01 / 03
Unit
Name the company, product or project being assessed.
Module 02 / 03
Coverage
Compare the requested activities with the existing inventory.
Module 03 / 03
Method
Identify the appropriate method for that accounting unit.
What should be checked before reusing a figure?
Use this editorial reuse check when an inventory result leaves the accounting team.
| Record or decision | What to preserve | Why it matters |
|---|---|---|
| Recipient | Record the actual question | Avoid an unlabelled footprint. |
| Perimeter | State entities and activities | Explain the result’s coverage. |
| Version | Retain the approved working reference | Prevent stale totals being circulated. |
How can software or advisory support be evaluated?
Ask for the accounting decisions and usable working evidence rather than an unsupported claim that a footprint is certified Inventory versus verification.
Module 01 / 04
Demonstrate
Trace one original source record through calculation to export.
Module 02 / 04
Correct
Replace a record and inspect affected calculations and approvals.
Module 03 / 04
Explain
Ask who resolves boundaries, estimates and reporting-method decisions.
Module 04 / 04
Transfer
Check access to the working files at the end of the engagement.
Read the detailed guidance and evidence
The carbon software guide covers the buying decision without changing this page’s focus on accounting method.
Use reporting consultancy for a defined professional brief and assurance for a separate engagement.
Use the standards overview to identify the reporting framework that will receive the inventory information.
Use the UK carbon reporting requirements map to separate the reporting outputs and evidence needed for each applicable route.
Use the Scope 2 software guide to test electricity records, method choices, instrument evidence and reproducible exports.
How can the work be organised?
This nine-step sequence is an editorial workflow rather than a statutory timetable.
- 101
Define the purpose
Write the inventory purpose, reporting unit and intended recipients. - 202
Set the boundary
Record the selected approach and evidence behind each operation’s treatment. - 303
Map the activities
Reconcile source lists and screen the relevant indirect activities. - 404
Allocate ownership
Give each collection stream a named owner and a review point. - 505
Select the methods
Record activity units, method choices and factor versions before calculation. - 606
Resolve the gaps
Estimate transparently where needed and retain an improvement action. - 707
Calculate and test
Reproduce selected records and inspect overlaps and unexplained variation. - 808
Approve the account
Review totals with their boundary, uncertainty and change explanations. - 909
Hand over the evidence
Export the working and retain the information needed for the next period.
Frequently asked
Questions people ask
Is carbon accounting the same as carbon reporting?
Accounting prepares the inventory, while a reporting rule or recipient determines which information must be disclosed.
Does a footprint include only carbon dioxide?
The Corporate Standard covers seven greenhouse gases, with results expressed using the appropriate carbon-dioxide-equivalent treatment.
Can all activity be calculated from spending?
No, because activity-based and spend-based methods use different inputs and should be selected appropriately rather than applied indiscriminately.
Are missing records zero emissions?
A missing record does not establish no activity, and the 2026 factors correction explicitly distinguishes unavailable data from zero values.
Can offsets reduce the inventory total?
Keep gross inventory emissions separate from offset or credit information rather than deducting a purchase from the source calculations.
Does using software provide independent assurance?
No, because an inventory and its calculation tools are different from a verification engagement and conclusion.
The ISO 14064 standards guide provides a separate route for choosing and describing the proposed GHG statement basis.
For a single product study, the product carbon-footprint guide starts with the unit, system boundary and intended claim rather than an organisation-wide annual total.
Sources
Primary sources
Primary provisions and official owner guidance checked on 26 October 2026; historical and draft resources are labelled in the guide.
- GHG ProtocolCorporate Standard: purpose and gases
- GHG ProtocolCorporate Standard, revised edition: Chapters 1, 3–7 and 9
- GHG ProtocolCalculation tools FAQ: sources, gases and biomass
- GHG ProtocolCalculation tools and guidance
- GHG ProtocolScope 2 Guidance: purchased-energy boundary
- GHG ProtocolCorporate Value Chain Scope 3 Standard
- GHG ProtocolScope 3 Calculation Guidance: activity-specific methods
- DESNZ2026 conversion factors and July correction
- DESNZ2026 methodology: units, fuels and global warming potentials
- UK governmentEnvironmental Reporting Guidelines including SECR