An Open Standard Framework for Consumer Carbon Calculations based on payment transactions

The Open Standard provides requirements and guidance for companies and organizations that want to estimate carbon footprint based on transaction data.

The goal is to promote sustainable consumption by linking climate currency to fiat currencies.

The increasing inclination of people towards sustainable consumption to mitigate their impact on global climate change has led to the emergence of financial technology (fintech) solutions designed to help users make informed and meaningful actions. The proper design of such consumer carbon tools requires careful consideration of data and collection methods, means of calculation, eventual usage, and understanding of how the tool influences its users. These should be encoded in corresponding standards that ensure they contribute to the broader purpose – environmental sustainability. This Open Standard for consumer carbon calculations based on payment transactions closes the gap.

1. Purpose of this Standard

The goal is to promote sustainable consumption by linking climate currency to fiat currencies. People’s spending behavior reflects their lifestyle. The Open Standard for consumer carbon calculations based on payment transactions provides a standardized approach for estimating carbon intensity factors (CO2e/monetary unit) for specific household consumption expenditure categories.

This standard aims to help users achieve the following:

  • Estimate carbon intensity factors for different consumption categories that can be replicated, tested and improved upon.
  • Ensure consumption information enables climate action.
  • Publicly reporting carbon intensity factors and methods and meeting stakeholders demands transparency.

The objectives of the Standard are:

  • To put the end-user and transparency at the centre of the processes.
  • Define a standardized method for calculating carbon intensity factors for different consumption categories.
  • Ensure data is collected and structured in a standardized manner that facilitates its use in drawing valid conclusions (i.e., in creating information) and enables its integration into related products and services.
  • Ensure that actions enable desired climate outcomes.
  • Discover and elaborate upon the major dimensions required to implement a fintech carbon-to-purchase system to design flexible solutions for all interested parties, enabling broad adoption.
  • To help users to provide accurate, consistent, transparent, complete, and relevant information.
  • To support consistent and transparent reporting for comparison purposes and continued improvement.
  • To create international consistency and transparency in how information is provided to the end-user.
  • To establish a quality management system for the community that provides carbon intensity factors based on payment transactions.

2. Primary users

This Standard is primarily for companies, entities, and organizations that want to estimate carbon footprint based on transaction data. National and subnational government entities might also find this standard useful to track changes in carbon intensities for different consumption categories at the household level in their respective countries.

The term “user” refers to the company, entity, or organization implementing the Standard; “end-user” refers to the individual using the application or bank interface, using the information generated when implementing this Standard.

3. Principles

To estimate carbon intensity factors, we apply generally accepted principles to ensure that the reported information represents a faithful, true, and fair account of Greenhouse Gases emissions. These principles are transparency, data integrity, relevance, and localization and are aligned with GHG Protocol (Figure 1).

4. Implementation steps

This Standard is organized according to the steps required when the user provides the end-user with  “carbon calculations based on payment transactions” (TtC). Depending on the objective, users may not need to follow all the steps shown in the figure below. If users have already analyzed the context, the guidance in step 1 may be skipped, but all users shall follow all other steps if aiming for verification based on this Standard.

01 Context Analysis
02 Estimation of carbon intensity factors
03 Alignment with the merchant codes
04 Implementation
05 Verification
06 Reporting
Open Standard Transaction to Carbon steps

Context Analysis

Calculating the carbon intensity per monetary unit of personal consumption requires a thorough revision and critical analysis of country-specific data. Thus, the first step is to identify context information about the country and national data sources available that will provide a reference to set the base values. Public emissions accounting frameworks - developed for National Accounts - possess attributes of relative simplicity and modularity, which make them worthy of consideration as a starting point for the development of consumption-based accounting.


Estimation of carbon intensity factors

The approach mainly relies on the household consumption model based on expenditures using Input-output tables available for the country under analysis. The EEIO-hybrid approach uses data from Environmentally extended multi-regional input-output tables or EE-MRIO. For the European Union, EXIOBASE 3 provides a time series of environmentally extended multi-regional input‐output (EE MRIO) tables ranging from 1995 to 2011 for 44 countries (28 EU members plus 16 major economies) and five rest of the world regions. To associate the emissions from EXIOBASE 3 with individual consumption, the user shall apply consumer expenditure data using the Classification of Individual Consumption by Purpose (COICOP). By dividing the emissions by expenditure data, an average carbon footprint is calculated on a consumption-category basis.


Alignment with the merchant codes

Carbon intensity factors are measured in CO2e per monetary unit. To provide individual carbon footprint based on one unit of currency purchased in each category, the user shall correctly align the end-user transaction per consumption category. To do this, the user should revise the bank transaction code information. The transaction code information aims to deliver a harmonized set of codes applied in bank-to-customer cash account reporting information. The bank transaction code information allows the account servicer to correctly report a transaction, which will help account owners perform their cash management and reconciliation operations. For more details about the calculations, please visit



The algorithm defining the procedure for linking the carbon intensity factors with the transaction data, listing the instructions to conduct the alignment, and selecting the carbon intensity may be proprietary information. Therefore, it is beyond the scope of this Standard. It is a core element in measuring performance. The user should write an algorithm that could become available to be public at any time.



Verification is related to quality assurance and quality control. Verification assesses whether the reported information is relevant, complete, accurate, consistent, transparent, and without material misstatements, thereby providing assurance or confidence in the findings. Carrying out verification gives the stakeholders and end-users confidence in the report’s results. Depending on stated objectives and circumstances, users should use any combination of verification and QA/QC.



Applying the transparency principle, it is recommended that when carbon intensity factors are estimated for a specific country, the user prepares a country profile and makes it publicly available. The Standard proposes a basic structure for the country profiles, which can be enhanced if necessary. For examples of the country profiles, please visit

Click here to download the Open Standard
Click here to learn more about the „Transaction to Carbon Methodology“
Country Profiles - Reporting carbon intensity factors
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