Understanding your bills
When calculating your carbon footprint you will need to collect data from your energy bills.
Understanding your electricity bill
Understanding your gas bill
Understanding your electricity bill
If you have all your electricity bills for the last year:
- Find the total kWh usage for each bill. Not all bills are the same so have a look on the front and the back of the bill for the total kWh for that billing period.
- Add these up to get your total energy use for the year.
* Make sure that you are adding up the bills for a 12 month period. If you are billed every quarter (most electricity providers do this) then you should have 4 bills to add up. If you include more or less bills than the 12 month period, your result will not be accurate.
If you only have the most recent bill:
- Look for the bar graph showing either total energy usage for the billing periods in the past year or the average daily usage for the billing periods in the past year.
If the bar graph shows total energy usage, add up the amounts noted above the columns for the last 12 months which translates usually to the last 4.
See the example below for guidance:
| Electricity | Quarterly total (kWh) |
| Period 1 | 523 |
| Period 2 | 621 |
| Period 3 | 395 |
| Period 4 | 471 |
| Total: | 2010 |
Put the total, in this case 2010 kWh, into the online calculator.
If the bar graph shows the average daily usage, find those figures and times them by the days of that billing period (usually 90 for electricity bills). It can be hard to find the figures depending on the scale of the bar chart but have a go!
See the example below for guidance:
| Electricity | Average daily use (kWh) | x Days | Quarterly total (kWh) |
| Period 1 | 5 | x 90 | 387 |
| Period 2 | 6.5 | x 90 | 360 |
| Period 3 | 4 | x 90 | 585 |
| Period 4 | 4.3 | x 90 | 480 |
| Total: | 1782 |
Put the total, in this case 1782 kWh, into the online calculator.
Understanding your gas bill
If you have your gas bills for the last year:
- Find the total Megajoules (MJ) for each bill. Not all bills are the same so have a look on the front and the back of the bill for the total MJ for that billing period.
- Add these up to get your total gas usage for the year.
* Make sure that you are adding up the bills for a 12 month period. If you are billed every two months (most gas providers do this) then you should have 6 bills to add up. If you include more or less bills than the 12 month period, your result will not be accurate.
If you only have the most recent bill:
- Look for the bar graph showing either total gas usage for the billing periods in the past 12 months or the average daily usage for the billing periods in the past 12 months.
If the bar graph shows total gas usage, add up the amounts noted above the last, usually 6, columns.
See the example below:
| Gas | Bimonthly total (MJ) |
| Period 1 | 6708.14 |
| Period 2 | 18475.89 |
| Period 3 | 18998.85 |
| Period 4 | 6610.06 |
| Period 5 | 3083.14 |
| Period 6 | 1160.28 |
| Total | 55036.36 |
Put the total, in this case 55036.36 MJ, into the online calculator where it asks for your gas usage for the year.
If the bar graph shows the average daily usage, find those figures and times them by the days of that billing period (usually 60).
See the example below for guidance:
| Gas | Average daily use (MJ) | x days | bimonthly total |
| Period 1 | 48 | x 60 | 2880 |
| Period 2 | 73 | x 60 | 4380 |
| Period 3 | 70 | x 60 | 4200 |
| Period 4 | 41 | x 60 | 2460 |
| Period 5 | 25 | x 60 | 1500 |
| Period 6 | 21 | x 60 | 1260 |
| Total: | 16680 |
