Selecting a Calculation Methodology

As organizations identify relevant emissions sources and compile business activity data (such as fuel consumed, dollars spent, or miles traveled), they gain clarity on what data is available and which calculation methods are feasible. Selecting from multiple calculation methods allows organizations to use available data today while improving data quality and methodologies over time.

The table below provides examples of different calculation methods across Scope 1, 2, and 3 emissions. In general, methods that rely on more specific activity data tend to produce more accurate emissions estimates, while methods requiring less detailed data are often easier to implement. As a result, there is typically a tradeoff between data availability, effort, and accuracy.

Spend- or distance-based methods are often appropriate starting points for organizations in the crawl stage. As data quality improves and processes mature, organizations may adopt more granular methods to improve accuracy where feasible.

How to Choose a Scope 3 Calculation Method (Decision Flow)

Step 1: Do you have supplier-specific or activity-specific data?

Yes → Use a supplier-specific or activity-based method (e.g., hybrid or direct calculation).

‍No → Move to Step 2.

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‍Step 2: Do you have detailed activity data (e.g., distance, quantities, energy use)?‍

‍Yes → Use an activity-based method (distance-, fuel-, or energy-based).

‍No → Move to Step 3.

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‍Step 3: Do you have reliable spend (financial) data?‍

‍Yes → Use a spend-based method (commodity or industry average).

‍No → Use secondary data and assumptions to establish a baseline.

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Step 4: Is this category a significant contributor to your total footprint?‍

‍Yes → Plan to improve data quality over time by engaging suppliers and replacing estimates with more specific data.

‍No → Maintain the current method and revisit as priorities change.

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Case Study: Agora

For example, when estimating emissions from employees traveling to quarterly offsites, Agora must select a calculation method based on available data. The organization may have access to the amount spent on travel, the distance traveled, or, in some cases, fuel consumption data.

In selecting a method, Agora considers:

• Data availability and quality: Which data is readily available, and which option produces the most reliable estimate?
• Cost and effort: Higher-quality data often improves accuracy but may require additional effort to source, prepare, and maintain.

Based on the data selected, Agora may use one of the following calculation methods:

• Spend-based: Uses the monetary amount spent on business travel, sourced from expense systems or financial records. This method is easy to implement but generally produces less precise estimates.
• Distance-based: Uses the physical distance traveled, typically sourced from travel booking systems. This method often provides a more accurate estimate than spend-based approaches and is commonly used for business travel.
• Fuel-based: Uses the volume or mass of fuel consumed and generally produces highly accurate results when fuel data is available. This approach is most applicable to company-owned vehicles or logistics activities and may not be feasible for all travel types.

Agora recognizes that higher-quality activity data supports more accurate emissions calculations, which in turn enables more meaningful insights and more effective decarbonization strategies.