Worked Examples and Comparison Checklists
How to read your electricity bill: a worked example line by line
A line-by-line worked example of an Australian electricity bill — supply charge, peak and off-peak usage, controlled load, solar credits, GST and concessions — with the maths shown.
To check an Australian electricity bill, multiply each usage line's kWh by its rate, multiply the daily supply charge by the number of days, subtract solar feed-in credits and concessions, and compare the total with what the bill says. If your total matches, the bill is arithmetically right; the next question is whether the rates are the ones in your plan and whether the readings are actual or estimated. This guide works through a full illustrative bill so you can do the same with yours, and shows where to find your NMI, tariff and best offer message.
Where things are on a typical bill
Bills differ by retailer, but the AER's Better Bills Guideline (for NSW, Queensland, South Australia, Tasmania and the ACT) requires a simpler front page with key information, and Victoria has its own bill content rules. Look for:
- Amount due and due date
- Billing period and number of days
- Plan name and whether it is a market or standing offer
- Best or better offer message: whether the retailer has a cheaper plan for you
- NMI and meter number
- Read type: actual (A) or estimated (E)
- Usage and charges breakdown
- Concessions and credits
- Comparison of your average daily usage with similar households
The illustrative bill
Illustrative figures only. A 92-day bill for a household in a time-of-use plan with a controlled load hot water circuit and rooftop solar.
| Line | Quantity | Rate | Amount |
|---|---|---|---|
| Daily supply charge | 92 days | 115.00 c/day | ? |
| Peak usage | 410 kWh | 44.00 c/kWh | ? |
| Shoulder usage | 320 kWh | 31.00 c/kWh | ? |
| Off-peak usage | 290 kWh | 22.00 c/kWh | ? |
| Controlled load | 560 kWh | 19.50 c/kWh | ? |
| Solar feed-in | 780 kWh | 3.00 c/kWh | ? (credit) |
| State concession | — | — | ? (credit) |
Working it out
Supply: 92 × $1.15 = $105.80
Usage:
- Peak: 410 × $0.44 = $180.40
- Shoulder: 320 × $0.31 = $99.20
- Off-peak: 290 × $0.22 = $63.80
- Controlled load: 560 × $0.195 = $109.20
- Usage total: $452.60
Charges before credits: $105.80 + $452.60 = $558.40
Solar credit: 780 × $0.03 = −$23.40
Concession: suppose the household receives a state concession of $90 for the period (illustrative). −$90.00
Amount due: $558.40 − $23.40 − $90.00 = $445.00
Residential rates on plan documents and bills generally include GST, and many bills show the GST component separately. If your bill lists rates excluding GST, multiply by 1.1 before comparing.
What the numbers tell you
- Average daily cost before credits: $558.40 ÷ 92 = about $6.07.
- Average daily general usage: (410 + 320 + 290) ÷ 92 = about 11.1 kWh; controlled load adds about 6.1 kWh a day.
- Peak share: 410 ÷ 1,020 = about 40% of general usage is at peak. Moving some of this to off-peak or midday would reduce the bill; see the flat versus time-of-use worked example.
- Solar: exporting 780 kWh earned only $23.40. Using more of that solar at home would be worth far more; see the solar exports worked example.
You can estimate the next quarter quickly with the quarterly bill estimator.
Checks to make on every bill
| Check | What to look for | If wrong |
|---|---|---|
| Rates match plan | Same supply and usage rates as your fact sheet or latest price change notice | Ask retailer; see mistakes guide |
| Read type | Actual (A) vs estimated (E) | See estimated bills and back-billing |
| Days | Billing period length | Longer periods mean larger bills |
| Discounts | Conditional discount applied if you paid on time | Ask retailer |
| Concessions | Applied each bill | Confirm eligibility details are current |
| Best offer message | Whether a cheaper plan exists | Ask to move, or compare elsewhere |
Gas bills: the same method with MJ
Gas usage is measured by volume and converted to megajoules: MJ = volume × heating value × pressure correction factor, all shown on the bill. Then apply the usage rates, which are often stepped (for example, a higher rate for the first block of MJ in the period). Add the daily supply charge. Illustrative: 12,000 MJ, first 2,000 MJ at 4.5 c and the rest at 3.8 c, supply 90 c/day for 90 days: $90 + $380 + $81 = $551.
FAQ
What is the NMI and why do I need it?
The National Meter Identifier is a unique 10 or 11 character number for your electricity connection. Comparison sites and new retailers use it to identify your meter and usage.
Why is my bill higher than last quarter with similar usage?
Check the number of days, the rates (a price change may have applied part-way through), whether a discount or concession dropped off, and whether the read was estimated.
Should the bill show a cheaper plan?
Bills in NECF states carry a better offer message under the AER's guideline, and Victorian bills carry a best offer message. If it says a cheaper plan exists, ask to move.
Who checks that the meter is right?
Your metering provider and distributor. If you think the meter is faulty, ask your retailer to arrange a meter test; a fee may apply if no fault is found.
Sources
- Australian Energy Regulator — Better Bills Guideline and retail rules
- Energy Made Easy — understanding your bill
- Essential Services Commission — Victorian bill and best offer requirements
- Victorian Energy Compare — Victorian comparison and bill help
