Total number of people in this home - This is often higher than the number above (for example if you are doing a calculation for yourself only but you live with other people).

2 - For each fuel that you use (if you don't use a particular fuel leave that section blank) there's three ways you can complete the table below. Each option on this list is less accurate than the one above so go for the highest one you can!:

a - Get all the bills for the last year and tot up the annual total. This is better than b as it takes into account seasonal variations in use. Don't worry, you don't need to go hunting for a calculator - there's one here. If you can't find all the bills but can find two bills that are a year apart and have your meter readings you can work out the difference - again you can use our calculator.

b - Find one bill and see how much you have used. Check the 'annual', 'monthly' or 'quarterly' box as appropriate before you type in the data.

c - Work out how much you spend on each fuel. This isn't so accurate but you could use it for a quick estimate as we usually have a rough idea how much we spend on each fuel. If you threw away your latest bill in a fit of despair at yet another price rise this is probably your best bet! Again, if you have monthly or quarterly data (perhaps from a bank statement) you can use our calculator to tot up your annual bill.

3 - Press submit after you have filled in the information for all of the fuels that you use.

Note - For electricity bills 1 'unit' on your bill = 1 KwH. However for gas 1 unit is not always equal to 1 KwH. Look at your gas bill for either a KwH equivalent or a 'therms', 'cubic m' or 'litres' figure and click the appropriate button in the gas section.

1 - Use the drop down menus to find the exact Co2 rating for your car. (This figure is the grammes of Co2 emitted per km traveled). If your car was made before 2000 select 2000 and pick the closest match.

2 - If you like you can give your car a name (eg. Mum's Car).

3 - Enter the total annual mileage for the car (including miles driven by other people who are not included in this calculation). Ideally this should be a figure for the most recent 12 months, but any 12 month period is fine as an estimate. Your last two MOT certificates should show the car's mileage approximately 12 months apart. You can use this calculator to work out the difference between these two amounts.

4 - If the car is only used by people who are in this calculation you can leave the 'My % Use' column at 100. If the car is used by other people click the blue heading below the table for more information on what to do.

5 - Press submit.

Should I include Business Journeys?

Probably not, but it's your decision. There are arguments for and against which are set out in our FAQ section.
 

My Green Debt provides two ways to record your flights:

Individual Flights. If you fly to a destination on a one-off or infrequent basis you can record each flight or return trip in the first table. If you use this approach additional flights to the same destination will have to be recorded separately.

Regular Flights. If you fly to a destination on a regular basis you can use the second table to work out the total carbon produced by all of your trips on one line.

Should I include Business Flights?

Probably not, but it's your decision. There are arguments for and against which are set out in our FAQ section.

The Wider Impact of Flying

Most scientists agree that the effect of flying on climate change is likely to be more than just the carbon dioxide produced. There are other gases produced by burning aviation fuels and the fact they are released high up in the atmosphere enhances their contribution to global warming. If you'd like to factor these effects into your calculation, just check the box below: (your Green Debt from flying will be 1.9 times higher than if you leave it unchecked). To read more about this issue click here.

My Green Debt provides two ways to record your rail, bus and boat journeys:

Individual Journeys. If you travel to a destination on a one-off or infrequent basis you can record each journey in the first table. If you use this approach additional journeys to the same destination will have to be recorded separately.

Regular Journeys. If you travel to a destination on a regular basis (more than once or twice a year) you can use the second table to work out the total carbon produced by all of your trips on one line. If you select the 'commute' option, My Green Debt will assume you make 5 return journeys per week for all but 6 weeks (holidays, sickness etc) of the year = 230 return journeys.

Should I include Business Journeys?

Probably not, but it's your decision. There are arguments for and against which are set out in our FAQ section.