Welcome

Welcome to BT's carbon calculator, which shows you what your annual CO2 usage is at any point in time. Annual CO2 usage is often referred to as a "CO2 footprint".

Before starting to use the calculator you'll need to have a few details to hand. You'll need your fuel and electricity bills, details of any flights during the past year, plus your yearly road and rail mileage. You only need to enter the details relevant to you in order to calculate your footprint. If any of the boxes aren't relevant, just ignore them. For instance, if you haven't flown anywhere in the last year, you don't travel by train or don't own a car, then skip those boxes.

Don't forget to hit "Calculate" after entering relevant details in the home, air, road and rail calculators. You will see your footprint building up at the foot of the table on the right hand side of the screen. When you have finished calculating, the pie chart will show how your footprint is made up.

You can now store your footprint by clicking on "footprint". This takes you to a screen that allows you to amend the details entered if you notice any mistakes. When you're ready, just hit "Save" to store your results.

When you know your CO2 footprint, you can go to the "Take Actions" section of the main website to see what you can do to reduce it.

As you take action to reduce CO2 emissions you can update the calculator as often as required and watch your CO2 footprint shrink.

Please note,when entering electricity usage in the home/office calculator, you can either use the UK average of 0.461 kg/kWh or replace this with the actual CO2 figure from your electricity supplier (this can range from over 0.6 kg/kWh to zero). If you don't have this figure, you can either call them or look it up on http://www.electricityinfo.org/suppliers.php.

This version of the calculator uses UK CO2 conversion factors. Future versions are expected to include conversion factors for other countries