Quick Summary
Scope 3 emissions – the indirect emissions in your company's value chain – are often the largest part of a company's total carbon footprint, particularly for businesses that buy in most of what they sell. Under the Australian Sustainability Reporting Standards (ASRS), companies in scope of mandatory climate reporting must disclose Scope 3 emissions. This guide covers what Scope 3 emissions are, why they matter, the Australian reporting requirements, how to calculate them, common mistakes, and how to automate Scope 3 data collection and reporting.
Table of Contents
- What Are Scope 3 Emissions?
- Why They Matter
- Australian Reporting Requirements
- How to Calculate Scope 3 Emissions
- Common Mistakes
- How to Automate Scope 3 Reporting
- Getting Started Checklist
- Frequently Asked Questions
What Are Scope 3 Emissions?
Scope 3 emissions are all indirect greenhouse gas emissions that occur in your company's value chain – both upstream (suppliers) and downstream (customers). They are defined by the GHG Protocol Corporate Standard, the international framework for carbon accounting.
The Three Scopes
| Scope | What It Covers | Examples |
|---|---|---|
| Scope 1: Direct Emissions | Emissions from sources your company owns or controls | Company vehicles, natural gas boilers, refrigerant leaks, on-site generators |
| Scope 2: Indirect Energy Emissions | Emissions from purchased electricity, steam, heating, and cooling | Grid electricity for offices, warehouses, factories; purchased steam and cooling |
| Scope 3: Value Chain Emissions | All other indirect emissions in your value chain | Purchased goods, business travel, employee commuting, waste, transported products, use of sold products |
The split between the three scopes varies a lot by industry. For many businesses, especially those that buy in most of what they sell, Scope 3 is the largest of the three.
The 15 Scope 3 Categories
The GHG Protocol defines 15 categories of Scope 3 emissions:
Upstream (Categories 1-8)
| Category | What It Includes | Data Sources |
|---|---|---|
| 1. Purchased goods and services | Emissions embedded in raw materials, supplies, and services you buy | Supplier invoices, procurement data, spend data |
| 2. Capital goods | Emissions from manufacturing equipment, buildings, and vehicles you purchase | Capital expenditure records, asset registers |
| 3. Fuel and energy activities | Emissions from extraction, production, and transportation of energy you use (not included in Scope 1 or 2) | Utility bills, energy procurement data |
| 4. Upstream transportation and distribution | Emissions from logistics, freight, and distribution of purchased goods | Freight invoices, logistics provider data |
| 5. Waste generated in operations | Emissions from disposal and treatment of waste generated by your operations | Waste disposal records, waste contractor data |
| 6. Business travel | Emissions from flights, accommodation, rental cars, and train travel for employee business travel | Travel booking system, expense claims, corporate credit card data |
| 7. Employee commuting | Emissions from staff travelling to and from work | Staff surveys, parking data, public transport subsidies |
| 8. Upstream leased assets | Emissions from assets your company leases (not included in Scope 1 or 2) | Lease agreements, property management data |
Downstream (Categories 9-15)
| Category | What It Includes | Data Sources |
|---|---|---|
| 9. Downstream transportation and distribution | Emissions from distribution and transportation of your sold products | Distribution contracts, logistics data |
| 10. Processing of sold products | Emissions from processing of your sold products by other companies | Product specifications, customer data |
| 11. Use of sold products | Emissions from customers using your products (if energy-intensive) | Product energy consumption data, customer usage surveys |
| 12. End-of-life treatment of sold products | Emissions from disposal of your products after use | Product lifecycle data, waste treatment data |
| 13. Downstream leased assets | Emissions from assets your company leases to others | Lease agreements |
| 14. Franchises | Emissions from franchise operations (if you are a franchisor) | Franchisee data |
| 15. Investments | Emissions from financed activities (for financial services companies) | Investment portfolio data |
Which Categories Apply to Your Business?
Not all 15 categories are relevant to every business. The material categories depend on your industry:
| Industry | Most Material Scope 3 Categories |
|---|---|
| Professional services | 1 (purchased goods/services), 4 (upstream transport), 6 (business travel), 7 (commuting) |
| Manufacturing | 1 (purchased goods), 2 (capital goods), 4 (upstream transport), 9 (downstream transport), 11 (use of products) |
| Retail | 1 (purchased goods), 4 (upstream transport), 5 (waste), 9 (downstream transport), 12 (end-of-life) |
| Financial services | 1 (purchased goods), 6 (business travel), 7 (commuting), 15 (investments) |
| Healthcare | 1 (purchased goods/medical supplies), 4 (upstream transport), 5 (waste), 6 (business travel) |
| Logistics | 1 (fuel, vehicles), 3 (fuel/energy activities), 4 (upstream transport), 9 (downstream transport) |
Why They Matter
Scope 3 emissions are not just a reporting requirement. They are the largest component of your carbon footprint and the most important lever for reducing your environmental impact.
The Business Case for Scope 3 Reporting
| Reason | Impact |
|---|---|
| ASRS compliance | Mandatory for Group 1 companies from 2025, Group 2 from financial years starting on or after 1 July 2026 and Group 3 from 1 July 2027 (ASIC RG 280). Scope 3 reporting is required, with relief in the first reporting period. |
| Supply chain pressure | Group 1 companies need Scope 3 data from their suppliers. If you supply a large company, they will request your emissions data. |
| Investor expectations | Institutional investors demand Scope 3 disclosure to assess climate risk in their portfolios. |
| Customer expectations | Consumers and B2B customers increasingly prefer suppliers with demonstrated sustainability commitments. |
| Cost reduction | Scope 3 analysis often identifies supply chain inefficiencies, excess packaging, and transport optimisation opportunities that reduce costs. |
| Competitive advantage | Companies that measure and reduce Scope 3 emissions early signal sustainability leadership to customers, investors, and talent. |
The Scope 3 Challenge
| Challenge | Impact |
|---|---|
| Data availability | Many suppliers do not measure or disclose their emissions, so you must estimate using spend-based methods or industry averages |
| Boundary setting | Deciding which value chain emissions to include and which to exclude is complex and requires judgment |
| Methodology | Multiple calculation methods exist (spend-based, average data, supplier-specific, hybrid), and choosing the right one requires expertise |
| Ongoing collection | Scope 3 data must be collected continuously from multiple sources, not as a one-time exercise |
| Assurance readiness | As assurance requirements tighten, your Scope 3 methodology must be auditable with documented data sources and calculation logic |
Australian Reporting Requirements
Who Must Report Scope 3?
| Reporting Group | Revenue Threshold | Scope 3 Requirement | Timeline |
|---|---|---|---|
| Group 1 (Large entities) | Two of: $500M+ revenue, $1B+ gross assets, 500+ employees | Required, with relief in the first annual reporting period | Reporting begins for financial years commencing on or after 1 January 2025 |
| Group 2 (Medium-large entities) | Two of: $200M+ revenue, $500M+ gross assets, 250+ employees | Required, with relief in the first annual reporting period | Reporting begins for financial years commencing on or after 1 July 2026 |
| Group 3 (Medium entities) | Two of: $50M+ revenue, $25M+ gross assets, 100+ employees | Required, with relief in the first annual reporting period | Reporting begins for financial years commencing on or after 1 July 2027 |
Source: ASIC RG 280, Table 2. NGER registered corporations and some funds and schemes are also brought in; RG 280 has the full table.
What the ASRS Requires for Scope 3
| Requirement | Detail |
|---|---|
| Disclosure of Scope 3 categories | Companies must disclose which of the 15 Scope 3 categories are included in their calculation and justify any exclusions |
| Calculation methodology | Companies must describe the methodology used (spend-based, average data, supplier-specific, hybrid) and the emissions factors applied |
| Data quality assessment | Companies must assess the quality of their Scope 3 data and describe improvement plans |
| Year-on-year comparison | Companies must compare Scope 3 emissions year-on-year and explain significant changes |
| Transitional relief | Scope 3 is not required in the first annual reporting period; companies should use that time to collect it |
The Assurance Timeline
| Year | Assurance Level | Scope 3 Coverage |
|---|---|---|
| 2025-2026 | Limited assurance on Scope 1 and 2 | Scope 3 not required in the first annual reporting period |
| 2027-2028 | Limited assurance may expand to include Scope 3 | Expect assurance on Scope 3 as data quality improves |
| 2029-2030 | Reasonable assurance expected | Full assurance on all disclosed metrics including Scope 3 |
How to Calculate Scope 3 Emissions
Step 1: Identify Material Categories
Not all 15 categories are relevant to your business. Use this decision tree:
Is this category significant relative to your estimated total Scope 3? → Include
Is data available for this category? → If yes, include. If no, estimate and note as improvement area.
Is this category required by ASRS for your industry? → If yes, include regardless of significance.
Step 2: Choose Calculation Methods
For each material category, choose the most appropriate calculation method:
| Method | When to Use | Accuracy | Effort |
|---|---|---|---|
| Spend-based | When supplier-specific emissions data is unavailable. Multiply spend by industry-average emission factor. | Low-medium | Low |
| Average data | When you know the quantity of goods/services purchased but not supplier-specific data. Multiply quantity by industry-average emission factor. | Medium | Medium |
| Supplier-specific | When suppliers provide product-specific emissions data. Use their disclosed emissions factors. | High | High |
| Hybrid | Combining spend-based, average data, and supplier-specific methods across different categories. | Medium-high | Medium-high |
Step 3: Collect Data
| Scope 3 Category | Primary Data Sources | Alternative Data Sources |
|---|---|---|
| Purchased goods and services | Supplier emissions disclosures | Spend data x industry-average emission factors (from Australian government or DEFRA factors) |
| Business travel | Travel booking system data | Expense claim data x distance-based emission factors |
| Employee commuting | Staff travel survey | Average commute distance x employee count x emission factor |
| Waste generated | Waste disposal records | Waste volume x waste-type emission factors |
| Upstream transport | Freight invoices | Spend on freight x transport emission factors |
Step 4: Apply Emission Factors
| Emission Factor Source | Coverage | Australian Relevance |
|---|---|---|
| Australian Government National Greenhouse Accounts (NGA) Factors | Electricity, fuel, transport, waste | High – designed for Australian context |
| UK DEFRA/BEIS Factors | Comprehensive (goods, services, travel, waste) | Medium – applicable to Australia with caveats |
| EPA (US) Factors | Comprehensive | Medium – applicable with regional adjustments |
| Supplier-specific factors | Product-level | High – most accurate when available |
Step 5: Report and Disclose
| Disclosure Element | What to Include |
|---|---|
| Total Scope 3 emissions | Total tonnes CO2e across all included categories |
| Category breakdown | Emissions by each of the 15 categories (where material) |
| Methodology | Calculation methods used, emission factors applied, data sources |
| Data quality assessment | Percentage of Scope 3 based on supplier-specific vs spend-based data |
| Year-on-year comparison | Change in Scope 3 emissions vs prior year, with explanation |
| Improvement plan | Actions to improve Scope 3 data quality and reduce emissions |
Common Mistakes
Mistake 1: Ignoring Scope 3 Because It Is Hard
The error: Companies report Scope 1 and 2 but omit Scope 3 because the data is difficult to collect.
The fix: The ASRS gives relief from Scope 3 in the first annual reporting period, but that time should go into collecting Scope 3 data. Start with the 3-5 most material categories and expand over time.
Mistake 2: Using Only Spend-Based Methods
The error: Calculating all Scope 3 categories using spend-based methods, which produce rough estimates that auditors may reject.
The fix: Use supplier-specific data where available (even for a subset of spend), average data for the next tier, and spend-based methods only for the long tail. A mixed-methodology approach produces higher-quality results.
Mistake 3: Not Documenting Methodology
The error: Calculating Scope 3 emissions without documenting the methodology, data sources, emission factors, and assumptions used.
The fix: Maintain a Scope 3 calculation workbook that documents every data source, every emission factor, every assumption, and every calculation. This workbook is your primary evidence for assurance.
Mistake 4: Treating Scope 3 as a One-Time Exercise
The error: Calculating Scope 3 emissions once for the first report and not updating annually.
The fix: Establish ongoing data collection processes. Connect to procurement systems, travel booking platforms, and waste contractor data feeds to collect Scope 3 data continuously.
Mistake 5: Not Engaging Suppliers
The error: Relying solely on spend-based estimates without asking suppliers for their emissions data.
The fix: Engage your top 20-50 suppliers (by spend) and request their Scope 1, 2, and 3 emissions data. Even if they cannot provide product-level data, company-level data is more accurate than spend-based estimates.
How to Automate Scope 3 Reporting
Manual Scope 3 data collection is the most time-consuming part of ESG reporting. Most of that time goes on pulling the same data out of the same systems every period, which is exactly the work automation handles well.
Manual vs Automated Scope 3 Reporting
| Aspect | Manual Approach | Automated Approach |
|---|---|---|
| Data collection | Manual extraction from procurement systems, travel platforms, waste records, supplier emails | Scheduled exports or integrations from your ERP, accounting, travel and waste systems |
| Spend-based calculation | Manual lookup of emission factors in spreadsheets, calculation in Excel | Emission factors mapped once to spend categories, then applied consistently each period |
| Supplier engagement | Manual emails to suppliers requesting emissions data, chasing responses | Standard data requests with tracked responses and scheduled follow-ups |
| Category classification | Manual assignment of purchases to Scope 3 categories based on supplier descriptions | Rules based on GL code and supplier that classify most purchases, with exceptions reviewed by a person |
| Report generation | Manual consolidation of data from multiple spreadsheets into ASRS disclosure format | A single calculation model that feeds the disclosure tables |
| Ongoing monitoring | Annual data collection exercise | Monthly or quarterly updates so the year-end report is not a scramble |
| Accuracy | Variable, depends on staff expertise and attention | More consistent, because the same documented methodology is applied every time |
Where to Start
- Connect the data sources: Procurement, accounting, travel booking and waste records hold most of the Scope 3-relevant data. Get it flowing into one place.
- Classify by rule: Map GL codes and suppliers to Scope 3 categories so most purchases classify themselves, and review the exceptions.
- Choose emission factors deliberately: Use the most accurate factor available (supplier-specific > average data > spend-based) and document the choice.
- Systematise supplier engagement: Send a standard request to your top suppliers by spend, track responses, and update calculations when supplier data arrives.
- Report from one model: Produce ASRS disclosures from a single documented calculation, covering all material categories with a data quality assessment.
- Track through the year: Monitor Scope 3 by category and supplier engagement progress, rather than starting from scratch each year.
Bottom Line: Scope 3 emissions are often the largest part of your carbon footprint and are required under ASRS for all reporting groups. The question is not whether to report Scope 3, but how efficiently you can collect, calculate and disclose the data. Automating the collection and classification steps cuts the most repetitive work and makes the result easier to assure.
Getting Started Checklist
Use this checklist to evaluate your Scope 3 readiness:
Data Availability
- Do you have procurement data (purchases by supplier, category, and amount)?
- Do you have travel booking data (flights, accommodation, car hire)?
- Do you have employee commuting data (survey results or estimated distances)?
- Do you have waste disposal records (volume by waste type)?
- Do you have freight and logistics data (transport spend, distances)?
- Do you have supplier emissions disclosures (any suppliers providing data)?
Calculation Capability
- Do you have access to emission factors (Australian NGA, DEFRA, or EPA)?
- Do you have a Scope 3 calculation workbook or tool?
- Have you identified which of the 15 categories are material for your business?
- Have you chosen calculation methods for each material category?
- Is your methodology documented (data sources, emission factors, assumptions)?
Reporting Readiness
- Can you produce a Scope 3 disclosure aligned with ASRS requirements?
- Is your calculation auditable (every number traceable to source data)?
- Have you assessed your data quality (percentage supplier-specific vs spend-based)?
- Do you have a year-on-year comparison baseline?
- Do you have a Scope 3 improvement plan?
Scoring Your Readiness
| Score | What It Means | Next Step |
|---|---|---|
| 0-5 checks passed | Minimal Scope 3 capability | Engage an ESG consultant for full readiness assessment |
| 6-10 checks passed | Some data collection exists | Begin Scope 3 calculation for 3-5 most material categories |
| 11-15 checks passed | Good Scope 3 foundation | Calculate all material categories, prepare first ASRS disclosure |
| 16-20 checks passed | Strong Scope 3 reporting posture | Focus on assurance readiness and continuous improvement |
Frequently Asked Questions
Do I have to report Scope 3 emissions if I am a mid-market company?
If you meet at least two of the Group 3 thresholds (revenue $50M+, gross assets $25M+, 100+ employees), you will be required to report from financial years commencing on or after 1 July 2027. Even if you are not yet directly in scope, if you supply goods or services to a Group 1 company, they will request your emissions data to complete their own Scope 3 calculation. This effectively puts reporting pressure on your supply chain regardless of your direct legal obligations.
What is the easiest Scope 3 category to start with?
Business travel (Category 6) is typically the easiest because travel data is usually well-recorded in booking systems and expense claims. Employee commuting (Category 7) is next easiest if you have staff survey data. Purchased goods and services (Category 1) is the largest but also the most complex – start with your top 20 suppliers by spend.
How accurate does my Scope 3 calculation need to be?
The ASRS gives relief from Scope 3 in the first annual reporting period, acknowledging that Scope 3 data is difficult to collect. During this period, spend-based estimates are acceptable if you document your methodology and describe your improvement plan. Over time, you are expected to move from spend-based to average data to supplier-specific methods as data becomes available.
Can Scope 3 data collection be automated?
Largely, yes. Integrations with your procurement, accounting, travel and waste systems can capture most Scope 3-relevant data, and rules based on GL codes and suppliers can classify most purchases and apply emission factors. A person still needs to review exceptions, supplier data and the final numbers. The human role shifts from data collection to data review and validation.
What if my suppliers cannot provide emissions data?
This is common, especially for small suppliers. In this case, use spend-based methods (spend x industry-average emission factor) as a starting point. As your suppliers mature, they will begin providing emissions data. Meanwhile, engage your top suppliers and encourage them to measure and disclose their emissions. Many suppliers will respond to customer demand by starting their own carbon accounting journey.
Ready to Automate Your Scope 3 Reporting?
Start by identifying your material categories and your top suppliers by spend, then document a spend-based baseline you can improve on. If you want help scoping your Scope 3 obligations and setting up the data collection behind them, see our ESG reporting service.