Scope 3 Category 1: Purchased Goods and Services Explained

What is Scope 3 Category 1: Purchased Goods and Services

Scope 3 Category 1 (PG&S) captures greenhouse gas emissions from the production of goods and services that your organization purchases from suppliers. These are upstream emissions - they occur before the products and services reach your facility.

Unlike Scope 1 (direct emissions from operations) and Scope 2 (purchased electricity), Scope 3 Category 1 represents emissions that happen in someone else's factory, farm, or office. The GHG Protocol Corporate Standard defines this as the most material category for many organizations, particularly manufacturers and retailers.

Understanding the Boundaries

Scope 3 Category 1 includes emissions from the full lifecycle of purchased items, from raw material extraction through to delivery to your gates. This covers everything from the steel in your manufacturing inputs to the business software you subscribe to, from office supplies to raw materials for production.

The key distinction is that you don't directly own or control these emissions - but you're responsible for accounting and reporting them. This applies regardless of whether suppliers are in your country or overseas, and whether you have direct contracts with them or purchase through intermediaries.

What's Included vs. Excluded

Included in Category 1:

• Raw materials and components purchased for production
• Packaging materials
• Business services (consulting, accounting, legal)
• IT services and software licenses
• Fuel and energy generation (but not the fuel itself if purchased separately - that's Scope 3 Category 3)

Excluded from Category 1:

• Capital goods (those go to Scope 3 Category 2)
• Fuel and energy purchases (Scope 3 Category 3)
• Transportation and distribution (Scope 3 Category 4 and 9)

Why Scope 3 Category 1 Matters for Your Carbon Footprint

For most organizations, Scope 3 Category 1 represents 40-80% of total carbon emissions. This is especially true for manufacturers, retailers, and consumer goods companies with complex supply chains.

Understanding and reducing Category 1 emissions is critical because:

Scale of Impact: A single purchased material can account for thousands of tonnes of CO2 equivalent depending on production methods. For example, primary aluminum production emits 10-15 tonnes CO2e per tonne of aluminum, while recycled aluminum emits just 0.5-1 tonne.

Cost Implications: Scope 3 reductions often align with supply chain efficiency improvements, waste reduction, and sustainable sourcing - all of which drive cost savings alongside emissions reductions.

Stakeholder Expectations: Investors, customers, and regulators increasingly demand transparency on supply chain emissions. Under frameworks like CSRD and SECR, reporting Category 1 emissions is often mandatory, not optional.

Risk Management: Supply chain disruptions, resource scarcity, and carbon pricing mechanisms make understanding upstream emissions essential for business resilience planning.

Three Calculation Methods for Scope 3 Category 1

Organizations can choose from three approaches, each with different accuracy levels and data requirements.

Spend-Based Approach

This method multiplies your spending on goods and services by average emissions factors. It's the quickest entry point for organizations starting their carbon accounting journey.

You'll use databases like Exiobase, USEEIO, or commercial emissions factor libraries to find typical emissions per dollar spent. For example, if you spend £100,000 on steel and the emissions factor is 3 kg CO2e per £1, your emissions = 300 tonnes CO2e.

Advantages: Low data burden, quick calculation, good for baseline emissions. Disadvantages: Less accurate, doesn't reflect your specific supplier practices, sensitive to currency fluctuations.

Activity-Based Approach

This method multiplies physical quantities of purchased materials (tonnes, units, volume) by their specific emissions factors.

Instead of spending data, you gather: quantity of steel purchased (tonnes), quantity of cardboard (tonnes), number of components sourced, etc. Then apply material-specific emissions factors from industry databases.

Advantages: More accurate than spend-based, reveals which materials drive highest emissions, supports targeted reduction efforts. Disadvantages: Requires detailed procurement data, suitable for organizations with standardized purchasing.

Supplier-Specific Data

The most accurate method uses primary data directly from your suppliers' own Scope 1 and 2 emissions, or their verified life cycle assessments (LCAs).

This involves requesting emissions data from key suppliers, often through questionnaires or CDP Supply Chain programs. You then calculate your share based on purchase volume or proportion of their output.

Advantages: Highest accuracy, reflects actual supplier practices, enables supplier engagement, supports credibility with stakeholders. Disadvantages: Resource-intensive, requires supplier cooperation, longer implementation timeline.

Overcoming Data Gaps and Common Challenges

Most organizations face significant challenges collecting complete data for Scope 3 Category 1. Here's how to address them:

Limited Supplier Data

Start with your highest-impact suppliers (typically 80% of emissions come from 20% of suppliers). Request emissions data from these critical partners first, then expand coverage gradually.

Use hybrid approaches: combine supplier-specific data for top suppliers with spend-based or activity-based methods for smaller vendors.

Currency and Pricing Volatility

When using spend-based methods, normalize spending data to a consistent currency and time period to avoid distortions from exchange rate fluctuations.

Consider using physical quantity data (weight, units, volume) instead of financial data where possible, as this eliminates currency issues entirely.

Supplier Reluctance to Share Data

Position data requests as a collaborative opportunity, not compliance burden. Offer to share your own emissions benchmarks and publicly recognize suppliers meeting emissions reduction targets.

Many suppliers are calculating their own Scope 3 emissions and may already have this data available - they simply need assurance it won't be misused.

Incomplete Product Specifications

Work with your procurement team to standardize product specifications in your systems. Ensure procurement records capture enough detail (material type, quantity, grade, origin) to support emissions calculations.

How to Calculate Scope 3 Emissions provides deeper guidance on data structuring for calculation purposes.

FAQ

What's the difference between Scope 3 Category 1 and Category 2?

Category 1 covers consumable goods and services used in operations. Category 2 includes capital goods - assets like machinery, vehicles, and buildings that you purchase and own. Capital goods have longer useful lives and are typically calculated separately with depreciation methods.

How do I decide which calculation method to use?

Start with your current data maturity: spend-based is fastest for initial baselines, activity-based works well if you have detailed procurement records, and supplier-specific data should become your target for high-impact suppliers. Many organizations use a hybrid approach.

Is Scope 3 Category 1 mandatory to report?

Under CSRD (EU), yes - all Scope 3 categories including Category 1 are mandatory if material. Under SECR (UK), Scope 3 is voluntary but increasingly expected. GHG Protocol recommends accounting for it regardless of regulatory requirements due to its typical material impact.

When should I recalculate my Scope 3 Category 1 emissions?

Annually is standard practice. However, recalculate immediately if: major suppliers change, product sourcing shifts geographically, supply chain structure changes significantly, or new emissions data becomes available from suppliers.

How can Greenio help with Scope 3 Category 1 accounting?

Greenio's platform integrates spend data with emissions factor databases, enables supplier data collection and management, supports hybrid calculation approaches, and provides year-on-year tracking. This reduces manual effort and improves data consistency across your organization.

Conclusion

Scope 3 Category 1 emissions represent your largest opportunity for carbon reduction and the most material component of most organizations' carbon footprints. While calculating these emissions requires effort - especially for larger organizations with complex supply chains - the investment pays dividends in cost savings, risk management, and stakeholder confidence.

Start with your highest-impact suppliers and highest-impact materials. Use a phased approach, beginning with spend-based calculations to establish your baseline, then progressively incorporate activity-based and supplier-specific data as your program matures.

The organizations leading on carbon accounting in 2026 aren't waiting for perfect data - they're building momentum with the information they have today, improving rigor incrementally, and engaging suppliers as partners in emissions reduction. Your Scope 3 Category 1 program should follow the same trajectory.