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Step-by-step guide + tips for calculating your Carbon Footprint

Are you looking to calculate your organisation's carbon footprint? In this article, Marijn Kansen, Junior Sustainability Expert, provides you with a step-by-step guide and several tips.

Are you looking to calculate your organisation's carbon footprint? In this article, Marijn Kansen, Junior Sustainability Expert, provides you with a step-by-step guide and several tips. Calculating your carbon footprint might feel complex and overwhelming, but the insights you gain are definitely worth the effort.

Marijn recently calculated the carbon footprint of Hedgehog Company. Check out this example of a carbon footprint here:

Step 1: determine your relevant scopes 

How to calculate a carbon footprint is established in the Greenhouse Gas Protocol (GHG Protocol). To start, you need to determine which scopes are relevant for your organisation; this depends on the type of organisation you are, and whether you provide products or services.

Scope 1, your direct emissions, and Scope 2, your indirect emissions, apply to all organisations. However, Scope 3 is divided into various sub-scopes, and you choose which ones apply to your organisation. These emissions are the emissions from your supply chains and depend greatly on your type of organisation.

For Hedgehog Company, for instance, Scope 3.1 emissions, purchased goods and services, are relevant. Consider laptops, office furniture, but also our lunch. And that lunch is delivered by Albert Heijn, which is upstream transport. You also need to consider this, along with the waste, such as packaging, that comes with our lunch.

Hedgehog Company is a service organisation, but we also have one product. That is the Hedgehog Carbon Platform, the tool I also used to calculate this carbon footprint. Thus, the greenhouse gas emissions that occur from running this tool also fall within our carbon footprint.

example carbon footprint calculation

Step 2: choose the activity-based or spend-based method

Once you've determined the scopes in which your organisation's environmental impact lies, the next step is to calculate the actual emissions for each of those scopes. You can calculate your emissions in two ways: using activity-based and spend-based data.

The activity-based method provides the most accurate insight into your greenhouse gas emissions. With this calculation method, you calculate your environmental impact using the precise emission factors of the activity or product. For instance, to calculate our exact impact, I looked at our grocery orders for the impact of our groceries, and I sent out a survey among colleagues about their energy contracts to determine the impact of working from home. I did the same to calculate the impact of commuting.

Sometimes, it's not possible to work with activity-based data; for example, if there are too many individual items in this category. Consider the category "office supplies," which includes items like pens, staples, notepads, etc. These consist of individual parts, and mapping out the impact of all this is truly an endless task.

And sometimes, the emission sources can't be traced any more; for example, expenditures in the hospitality sector. If you only know the amount spent but not exactly what you ordered, the spend-based method then offers a way to say something about your environmental impact.

In such cases, you choose the spend-based method for that category, and you find an emission factor that fits this category of products. An example of such a category is "electronics." You then multiply the amount you spent on this category by the found emission factor, and thus you arrive at your emissions. But these are calculated based on general values, average emissions.

So, you decide per emission source whether you will calculate it activity-based or spend-based, where activity-based, where possible, is definitely preferred.

Read more about the difference between spend-based and activity-based data: Case CCV: Calculating the carbon footprint with activity-based data - Hedgehog Company (

spend-based activity-ased data
Data Hierarchy

Step 3: find your emission factors

The next step is to locate your emission factors. An emission factor is a figure that represents the amount of emissions from a source per unit of activity or consumption. It is used to calculate the environmental effects of various activities.

There are specific databases that contain emission factors for calculating your carbon footprint. For instance, you have the Dutch CO2 emission factors database and the UK's DEFRA database with GHG emission factors. There's also Exiobase, a monetary environmental extended input-output database, which allows you to calculate emissions based on the amount spent on a particular product or service.

For some emissions, I was able to use standard emission factors; if the factor is available in the databases we use, you can multiply it by your data. For example, if you know the emission factor for coffee beans and how many kilos we have consumed, you can easily do the math.

EcoInvent is an example of such a database. However, not all emission sources are included in it. If you cannot find a standard emission factor, choose the most representative one. There might not be an exact match for every type of transport, so then you select a general reference or the closest one available.

Once I had gathered all the data and associated emission factors, I entered it into the Hedgehog Carbon Platform to calculate our carbon footprint. This is how we found out that our carbon footprint in 2023 was 16 tonnes of CO2-eq.

When we perform a carbon footprint calculation for an organisation, we follow all the steps outlined above. All the data is then ready in a personalized environment, and the organisation can easily calculate its own carbon footprint. They can also enter new data to recalculate the carbon footprint at a later time.

By calculating your carbon footprint at different times, you can also see the development of your environmental impact over time.

What is the emission factor here?

What challenges did you encounter when calculating our carbon footprint?

There were several scopes where it was more difficult to determine appropriate emission factors. For example, every colleague at our office receives a pair of Adidas slippers to wear. We had the invoices with the total amount paid, but not the weights of all the slippers. In this case, we chose not to estimate the weight but to link an emission factor from the Exiobase database for rubber and plastic products to the total amount we spent on the slippers.

And the scope 1 and 2 emissions were difficult to determine in our case; these are emissions concerning, for example, your energy consumption. But we are in a shared office complex; our landlord could not provide us with precise consumption data. Therefore, I calculated these emissions using averages from the Central Bureau of Statistics.

This was regrettable because I wanted to calculate the carbon footprint as accurately as possible. And when you calculate using averages, rather than accurate data about your own specific situation, it's hard to devise a reduction strategy for these emissions.

impression carbon accounting software

What tip do you have for organisations that want to calculate their carbon footprint? 

A carbon footprint gives you a complete and concrete insight into your emissions. And yes, it can be quite complex to calculate this footprint. But I would say; don't be overwhelmed by this. The insights a carbon footprint provides make it definitely worth the effort.

And data collection can initially feel too complex. Therefore, create an overview; what data do you want to collect? What emission factors are available? For which sources do you need to establish appropriate emission factors? Once you have this overview and tackle it step by step, you will find that the actual calculation is manageable.

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