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Introducing our new carbon calculator

We've created a new tool that you can use to calculate how much carbon you save by travelling actively during the Step Count Challenge.

Published: 25/10/2021

Patrick Harvie MSP, Minister for Zero Carbon Buildings, Active Travel and Tenant's Rights, introduces the Step Count Challenge carbon calculator

If you’ve taken part in the Step Count Challenge before, you’ll probably have lots of fond memories of walks shared with family and friends, wandering through your local woods enjoying the smell of autumn air, or taking in a view that you’d never seen before. You might have even found yourself walking and cycling more than ever over the last eighteen months, exploring new routes and enjoying a chance to switch off and connect with nature.

Although dark winter nights and busier diaries mean that you might find yourself walking and cycling less often, it’s still important to find time to be active, look after your mental health and connect with your colleagues. The great news is that you can do all this, and help towards tackling the climate emergency too, by swapping short car journeys for walking, wheeling and cycling.

We’ve developed an exciting new tool for the Step Count Challenge website, which you can use to record journeys you’ve completed by walking, wheeling or cycling, instead of taking the car. You'll find this on your Dashboard when you Add Activity, simply click the tick box asking if your walking, cycling or wheeling activity was instead of taking the car. The carbon calculator will not only tell you how much carbon you’ve saved by leaving the car at home; it’ll also turn the amount of carbon you’ve saved into a virtual forest!

As the Step Count Challenge progresses, you’ll be able to record more and more active travel journeys, saving more carbon, and adding more trees to your virtual forest.

The technical bit

If you’ve never calculated your carbon before, you might be wondering how we’ve come up with our figures. In the same way as different types of physical activity have a different step count equivalent, different types of car have different emissions conversion factors – that is, the amount of CO₂e (carbon dioxide equivalent, a measure of all greenhouse gases combined and expressed as an equivalent of carbon dioxide) they emit per mile or kilometer.

To calculate the carbon emitted by a specific journey, the formula we’ve used is:

Distance travelled (kilometer) x carbon conversion factor = CO₂e (kg)

To gain an even more accurate calculation, we’ve given you the option of entering the type of car you would normally use – you can enter this by logging in to your account and clicking on your “Profile” tab.

Below is a table showing the emissions conversion factors per kilometer for different types of car, taken from the Department for Business, Energy and Industrial Strategy’s greenhouse gas reporting conversion factors 2021.




Plug-in Hybrid Electric

Small car





Medium car





Large car





Average car





To calculate how much carbon is emitted by, for example, a quick 2 km round trip to the shops in a medium petrol car, the calculation we’ve used is:

2 (km) x 0.18785 = 0.3757 kg CO₂e.

This means that, if you walked, wheeled or cycled for a 2 km round trip to the shops, you’d save 0.38 kg CO₂e.

This may not seem like much, but if you swapped a 2 km journey like this once a week during the four weeks of the autumn Step Count Challenge, you would save 1.52kg CO₂e. That’s roughly the same as large bag of flour!

If you’d like to see how much carbon you can save by swapping one of your regular car journeys for a walking, wheeling or cycling journey, give our new carbon calculator a try, and watch your virtual forest grow. And don’t forget that walking, wheeling and cycling can be combined with a train or bus journey too – every mile counts. Give your health a boost, connect with nature and help our environment this autumn by leaving the car if your journey isn’t far.