Calculating carbon footprints is much more than just multiplying numbers. When determining a carbon footprint, attention must be paid to several different things, including the goal setting and system boundary, the input data, the execution of the calculation, and the verification of the results. The calculation must follow the standards and guidelines so that result is reliable and the company can avoid greenwashing.

There are different standards for calculating carbon footprints, whether you are calculating the carbon footprint of a company, product, or project. All relevant carbon footprint calculation standards are based on the life cycle assessment standards ISO 14040 and ISO 14044.

When calculating the carbon footprint, all significant emission sources related to a specific identifiable entity are taken into account - in the case of product accounting, the product's entire life cycle from the cradle to the grave.

Carbon footprint calculation is based on the following steps.

Setting a goal for calculating a carbon footprint

The carbon footprint calculation begins with the definition of the business goal of the calculation. It is essential to consider whether you want to calculate the carbon footprint of an entire company or an individual product and what you want to use the calculation results for. Goal setting also affects the choice of the used standard.

A company’s carbon footprint is typically calculated per annum. When calculating the carbon footprint of a product, the so-called functional unit to which the carbon footprint is related must also be defined. Typically, a functional unit is one product or one kilogram of a product. Sometimes - especially when comparing different products - a functional unit can also be a sufficient number of products for a particular need.

Defining the system boundary

The goal set for the calculation affects how the system boundary is defined. The system boundary involves organizational and geographical boundaries and temporal scale. The organizational boundary can be defined based on the activities owned or controlled by the company. The geographical system boundary can be used to decide whether, for example, a company's country-specific or total emissions from its global operations are calculated. The time scale determines the period from which the input data used in the calculation is collected.

What kind of input data is needed for calculating a carbon footprint?

The input data required for the calculation are collected from all operations included in the system boundary. Two types of data are necessary for the calculation: the company's activity data and the emission factor data. Where possible, so-called primary data should be used in the calculation, i.e., data obtained directly from raw materials suppliers, for example. To the extent that such information is not available, emission factor data found in reliable databases may be used.

Carbon footprint calculation and reporting

Once the input data have been collected, the carbon footprint calculation is performed following the guidelines of the applicable calculation standard. When calculating the product-specific carbon footprint, the guidelines of the relevant product category rules are also taken into account.

The calculation method and results are presented in the carbon footprint report. The report also describes the goal set for calculation, system boundary, and the assumptions and uncertainties related to the calculation.

How do I know if the calculation result is reliable?

The reliability of the calculation results is evaluated in the carbon footprint report, for example, by sensitivity analysis. The reliability of the calculation and reporting can be further improved by independent third-party verification.

Once the carbon footprint has been calculated and reported reliably, the results can be communicated without fear of greenwashing.

What is OpenCO2.net?

We offer standard-based carbon footprint calculators built on the OpenCO2.net platform for calculating the carbon footprints of both organizations and products/services. We also provide Finland's most comprehensive emissions database with up-to-date emission factors. We grant the Carbon Footprint Label for verified calculations.