The methods and data behind Carbon Donut

The Carbon Donut app was developed to help you pinpoint where your carbon emissions come from, and to give you a tool that will help you see which decisions affect your emissions the most. The lifestyle emission calculator only includes data on emissions that you can actually control. Hence, it differs from your carbon footprint, which is calculated by dividing the overall greenhouse gas emissions of a nation by the number of citizens.

There are two versions of the lifestyle emission calculator — a full version available in Carbon Donut, and a shorter version available on our website. Both versions are based on the same methods and data, but the web-version contains fewer questions and the results are therefore not as accurate as in the app version.

All emissions are calculated per person. This means that if you live with a flatmate, we divide the emissions caused by building, heating and powering your home between you and your flatmate, resulting in half the emissions compared to if you were to be living alone. The same goes for car driving: the more people in the car, the lower the emissions per person!

Your lifestyle emissions are calculated for an entire year. So far, Carbon Donut only includes Finnish and Swedish data (and the web calculator only uses Finnish data), but we are working on adding data for other countries as well. Since Finnish and Swedish consumption patterns are very similar, Finnish data is used for both countries in most categories. However, since Sweden has much more emission-free electricity than Finland, we’re using country-specific emission coefficients for that. 

If you want to know what values and methods are used to calculate your lifestyle emissions, take a look at the descriptions for each category below:

Home & heat

Your lifestyle emissions include emissions from constructing, maintaining and demolishing the building you live in. These emissions are calculated based on: 

  • The type of house you live in, and 
  • The size of your home.

The emission factor for apartment buildings is 8.0 kg CO2-eq/m2 per year and for houses or terraced houses 6.9 kg CO2-eq/m2 per year (Saari, 2001). The emissions from construction, maintenance and demolishing are distributed over the lifetime of the building, which is assumed to be 50 years. 

Emissions from heating your home are calculated based on these input values:

  • The type of house you live in,
  • The size of your home, and 
  • The heating method you use.

The need for heating is partly based on the need for space heating, which is dependent on the size of your home, and partly based on the need for warm water (for things like showering, washing dishes and clothes, etc.), which is dependent on the number of people living in your home.

The amount of space heating needed per square metre of living space is typically dependent on when the house was built and what type of building it is. Here, an average is used for each house type: 92 kWh/m2 for apartments and terraced houses and 179 kWh/m2 for houses (VTT, 2018). An additional margin is added to these values to account for storage rooms, stairwells and other heated parts of the buildings that don’t count towards the living area. 

Heat required for hot water is then added to your yearly heat consumption. It is estimated to be 1000 kWh per person and year (Vattenfall, n.d.).  

The amount of heat you use is multiplied by an emission coefficient, which depends on which fuel is used, to determine the emissions that arise from it. The coefficients and information about the data are listed in the table below.

Table describing the carbon emissions from different heat sources.

*Life cycle emissions have been estimated and added to make these comparable with emissions from wood pellets.

In reality, emissions from district heating vary from city to city, but the calculator uses a national average to keep the test at a reasonable length.

If you have a summer house, the emissions required to heat and power it are added to your lifestyle emissions. The size of the summer house is assumed to equal the Finnish average, 74 m2. A typical Finnish summer house is shared by four people, so the total emissions for heating and powering the place is divided by four before being added to your emissions. (MMM, 2016)

The summerhouse is assumed to be heated by electricity (covering 80% of heating need) and pellet (covering 20% of heating need), since over half of Finnish summer houses are heated by electricity and almost all of them have a stove or similar for extra heat. The heat consumption and emissions are estimated using the same principles as above, except that there’s no extra margin added for storage rooms and stairwells, etc. It is also assumed that the temperature is kept a little lower during three winter months, when a majority of Finnish summer houses are reported to go unused. (MMM,2016.)

In terms of electricity, since most Finnish summer houses are equipped with fridges , we assume that if you have a summer house, you run two fridges simultaneously during 3 months per year (one at your summer house and one at your regular address). These extra emissions, though comparatively small, are added to your yearly emissions.


In the case of electricity, emissions are calculated in much the same way as for heat:

  1. The amount of electricity consumed is determined based on the size of your home and the number of people living in it. The calculator also takes into account whether you have a sauna and/or floor heating.
  2. The amount of emissions caused by electricity consumption is calculated by multiplying the kilowatt hours used by an emission coefficient, which is dependent on the type of electricity used.

Electricity consumption and emissions are calculated based on the formulas and data in the table below:

Table describing how electricity consumption has been calculated as well as the greenhouse gas emissions from different types of electricity sources.

In the case of certified renewable electricity, emissions are assumed to be zero. In other cases, we use the emission coefficient for the residual mix, which corresponds to the average emissions for all electricity consumed in a country, excluding certified green electricity. In other words, it is the average emission coefficient for electricity from fossil fuels, nuclear power, and non-certified renewable electricity, either generated in Finland or imported. (Energy Authority, 2021.)


The greenhouse gas emissions for different vehicle types have been obtained from the LIPASTO unit emissions database (VTT, 2017). LIPASTO reports so-called unit emissions, measured in grams per kilometre, or grams per passenger kilometre for public transport. Electric vehicles are an exception, in which case the electricity consumption per kilometre is presented instead. The emissions are then calculated by multiplying the electricity consumption with the emission coefficient for the Finnish electricity mix (the average emission coefficient for all electricity sources consumed in Finland), which is 131 g CO2-eq/kWh (Statistics Finland, 2021).

If you report using bio-based fuels, such as biogas or biodiesel, your emissions are reduced. For biogas, the emissions are assumed to be reduced by 85% compared to using regular gas (Gasum, n.d.). For biodiesel, the emissions are assumed to go down by 89% (Neste, n.d.). In case you have a hybrid car, we assume that half of the driving is powered by electricity. Hence the share of fuel that can be replaced by biodiesel is smaller, and emissions are reduced by 45%.

The calculator does not take life cycle emissions into account in its transport calculations. The only emissions that are included are the ones related to fuel consumption (or in the case of electric vehicles, emissions from electricity production). Emissions that arise during the manufacturing of vehicles or batteries for vehicles have been omitted.

Flights & ferries

Emissions from air and sea transport have  also been obtained from the LIPASTO database. Since flight emissions are highly dependent on the type of aircraft and the aircraft depends on the distance travelled, LIPASTO has split its data into emissions for short national flights, long national flights, short European flights, long European flights and intercontinental flights. The data is given as unit emissions in grams per passenger kilometre. The calculator transforms this data into grams per passenger hour using Finnair’s flight schedules for corresponding travel distances, since it’s often easier for users to estimate how much they fly in hours rather than in kilometres. It then calculates an average for all LIPASTO flight categories to estimate the emissions based on the input hours.

The LIPASTO data only includes direct emissions from burning the fuel. It does not take into account the radiative forcing index (RFI), which describes the effect of for example changes in ozone concentration and cloud formation. To counter that, the estimated flight emissions are multiplied by a factor of 1.5. This factor was chosen after comparing results for different flight routes with data from — a page that uses very precise data in terms of aircraft types and flight altitude. The factor is a little exaggerated for short flights (around 1 hour), but an underestimate for long intercontinental flights. 

In the case of ferries, the calculator uses the specific emissions for passenger ferries with a typical speed of 18 knots (the fuel consumption is tightly connected to the speed of ferries). This corresponds to a typical cruise ship trafficking the routes between Finland, Sweden and Estonia. Though these ships also carry cargo, a vast majority of  the emissions are allocated to the passengers, since most of the ship’s space is meant for passengers.


Carbon emissions from different food types have been retrieved from Mat-klimat-listan (Röös, E., 2012). The values that are reported there are average values based on a literature review, and contain all emissions related to production, processing and packaging. Transport from abroad has been included for such food types where it has a significant impact.

The total emissions for an average Finnish diet (called “I eat it all” in the calculator) have been calculated by multiplying these values with the average consumption data, obtained from Luonnonvarakeskus (2017). Total emissions for the flexitarian diet (“I try to eat less meat & fish”) has been calculated by replacing 50% of the meat and fish with an amount of beans adding up to the same protein intake, and by increasing cheese consumption by 15%, and nut consumption by 100%. For the pescetarian, meat has been replaced by beans, fish consumption has been increased by 20%, cheese consumption by 30%, and nut consumption by 150%.

In the vegetarian diet, both meat and fish have been replaced with beans. Cheese consumption has been increased by 30%, and nut consumption by 150%. For the vegan, meat, fish, eggs and dairy have been replaced by beans. Nut consumption has been increased by 300%, and rice by 100%. Consumption of fruits and vegetables have been increased for all types of diets compared to the average one. The amount of consumed vegetable oils has been increased for the pescatarian, the vegetarian and the vegan diet.


Emission data for consumption has been obtained from SYKE (2019), which uses the environmentally extended input-output model ENVIMAT. The data is given as kg CO2-eq per €, as well as average spending per year in euros, for different categories, including clothes, electronics, hobbies etc. 

The categories used by SYKE have been grouped into bigger entities to make the test easier to complete. These entities as well as resulting spending and specific emissions can be seen in the table below.

Table describing average yearly spending and the greenhouse gas emissions of different consumption categories.

Pets weren’t specifically mentioned in SYKE’s report, so it’s been taken out of the category Hobbies & services using data on average pet spending in Finland from Statistics Finland (2020). The emissions are assumed to be the same regardless of the pet, though in reality, the climate impact depends a lot on the amount and type of food the pet is fed.

For the first four categories listed in the table, you can define both how much you shop in each category. The shopping amount is described on a scale from 1 (“Very little”), which is defined as 20% of the average Finn, to 5 (“A lot”), which is defined as 200% of the average Finn. 3 (“Pretty average”) corresponds to the Finnish average spending, and the scale towards each end is linear. 

You can also define how much you shop second hand in the categories Clothes & shoes, Electronics, and Things for the home. Again, a 5-grade scale is used from “Never” to “Always”. If you select “Never”, your emissions within that consumption category remain the same, and if you select “Always”, they are reduced by 90%. 3 (“Sometimes”) means the emissions from that category drops by 40%. Again, the scale from the middle towards each end is linear.

The calculator only asks you about the first five categories, but there is some basic consumption that is assumed to be equal for everyone. The Basic consumption category includes for example internet connection, phone subscription, newspapers etc., and adds up to approximately 4% of the consumption emissions of the average Finn.

Do you have any questions about Carbon Donut or its data? Check out our Frequently Asked Questions, and don’t hesitate to contact us if you couldn’t find the answer!


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