Deciphering the carbon footprint of your transactions

How do you calculate my carbon footprint?

We certainly don’t want to leave a bad impression (got the little joke?), so we use the data and expertise of our trusted partner Connect Earth to provide carbon footprint estimates.

The carbon footprint of your purchases is calculated using «emissions factors» that are specific to the category and region of your purchase.

We multiply the transaction amount by the emissions factor relevant to the category of the transaction to estimate the carbon footprint.


Transaction amount x category «emissions factor»


Here’s an example of how this works:

1. You go to the supermarket and spend 20 CHF.

2. We multiply this by the emissions factor for food in your specific country (e.g. 0.48 kg CO2e/CHF).

3. This gives us an estimated carbon footprint of 9.6 kg of CO2e


Note, however, that the emissions from this could be very different from, for example, spending the same amount of 20 CHF in a bakery, which could be equivalent to 6 kg of CO2e. That’s why it’s only an «estimate» of emissions. However, the methodology used is the same as that used widely in industry and academia for carbon footprinting.

While the calculations ensure that your estimated emissions are as accurate as possible by categorising the retailer, the CO2 amounts you see in the app are estimates because we can’t see exactly what products you’ve bought.

How do you use my carbon footprint data?

The information used to calculate and provide you with emissions estimates for your transactions is only used for this specific purpose of providing information.

This data will not be used for any purpose other than to help you understand your carbon footprint. The carbon footprint information or any other inputs used will only be used for carbon insights and will not be sold to any other external third parties.

You can read our partners’ privacy policy for more information about their data processing and use.

As a UK-based company following data compliance standards such as GDPR and SOC2, Connect Earth takes data privacy and ownership very seriously and is audited annually for data privacy and security.

How do you know what I bought in a transaction? (E.g. groceries, fuel stations, Amazon)

Don’t worry, it’s not like Big Brother is watching you, because we don’t know exactly what was bought in a transaction. However, we can make an approximate industry standard carbon footprint estimate using the transaction category.

In our analysis, we categorise transactions according to the retailer they were made with. This is because we cannot see which specific products were included in a transaction. So we use industry averages for merchants to estimate the environmental impact of your spend, based on the typical environmental impact of products and services in that industry.

To explain how this works, here are a few examples:

Groceries: If you were shopping in a grocery store, we would make an estimate based on the environmental impact of a typical basket of groceries purchased in your country. This includes many things such as production, packaging and transport within the industry. In this way, we can give you an overall estimate of the carbon footprint associated with your spending habits, without requiring detailed information on each specific item you purchased.

Petrol stations: When buying fuel from a petrol station, no product weighting is required and the amount of fuel purchased can be accurately determined and the associated emissions calculated.

General stores (e.g. Amazon): Purchasing from general stores, including online retailers such as Amazon, where a wide variety of goods are available, again requires a weighted basket approach. Given the nature of the retailer, the resulting calculation will be a rough estimate for this transaction. Please note that for most users such purchases will typically only contribute a small amount to their overall carbon footprint, with the majority coming from other sources such as travel, home energy and food.

By using the retailer type to generate estimates, we aim to provide a simple and accessible way for you to understand and reduce your carbon footprint based on your spending patterns.

How accurate are the estimates shown in the app?

Think of the estimates in the app like a weather forecast – generally right, but don’t bet your umbrella on it. In other words: The estimates shown in the app provide a general and approximate indication of the environmental impact associated with your spending. While we strive for accuracy by using industry-standard emission factors and reliable data sources, it’s important to understand that these estimates are based on broad assumptions and may not account for variations in specific product choices or supply chains.

The accuracy of the estimates depends on the quality of the underlying data and the completeness of the industry averages. For most users, the app is a valuable and insightful tool for understanding the environmental impact of their spending patterns. However, it’s important to interpret the estimates as informed approximations rather than precise measurements.

As technology and data sources improve, we are continually working to improve the accuracy of our estimates to enhance your carbon insights. Your feedback and any additional information you provide can help refine our models and make the estimates more reliable over time. Our goal is to provide you with useful insights to help you make more sustainable decisions, while recognising the inherent limitations of estimates in the current state of environmental analysis tools.

Why is it important to learn about my carbon footprint?

Climate change is real, so measuring your carbon footprint is a great first step in the fight against it. With up to 60-70% of global emissions being directly or indirectly linked to household consumption, as a consumer you have a lot of power to influence global sustainability.

While your carbon footprint isn’t entirely your fault or responsibility, we believe it’s important to raise awareness of where our carbon emissions really come from. We can also help promote more sustainable consumption and production of goods and services around the world.

Carbon emissions have a significant impact on the environment, such as contributing to rising sea levels and higher temperatures, so any changes we can all make to reduce our carbon footprint can help reduce these negative global impacts.

How are the CO2e models made?

Our partner Connect Earth has an expert team of carbon scientists who work with universities and other research organisations to ensure that carbon models are as accurate as possible. They’re not just crunching numbers, they’re guardians of the globe, making sure they’re in line with industry and academic best practices to ensure they meet common standards and protocols such as the GHG Protocol.

Emissions calculation models are based on data from official government data and research, including sources such as leading EEIO models, OECD, Eurostat, DEFRA and many others.

The methodology is up to date with the latest carbon modelling expertise from industry and academia, meaning you get the same quality of emissions data for your spend as is used by governments and climate scientists.