How to Read Your Electricity Bill (and Spot the Costly Lines)
Supply charge, usage, demand and feed-in — what each line means, and the ones that quietly cost you the most.
Most electricity bills are designed to be paid, not understood. But once you know what each line does, you can see exactly where your money goes — and whether the fix is a behaviour change, a tariff change, or nothing at all. Here's how to read the bill you already have, from the top down.
The three charges that make up almost every bill
Strip away the branding and your bill is usually built from three mechanisms:
- Supply (service) charge — a fixed daily fee just for being connected, charged in cents per day regardless of how much power you use. You pay it even in a month you're on holiday with everything switched off.
- Usage charge — cents per kilowatt-hour (c/kWh) for the energy you actually consume. This is the line most people watch, and for many homes it's the biggest.
- Demand charge — a fee based on your highest rate of draw during a set window (often measured in kW or kVA), not your total usage. Common on commercial accounts and increasingly on residential plans with smart meters.
Add solar export credits (feed-in) and the picture is complete. The trap is assuming usage is the whole story — it often isn't.
Supply charge: the line you can't switch off
The daily supply charge is fixed, so it's a bigger slice of a small bill than a large one. If you're a low-use household or a holiday home, a high supply charge can quietly dominate your total. It's also the reason "use less" only takes you so far — you can cut usage to near zero and still owe the daily fee every single day of the billing period.
What to do: multiply the daily rate by the number of days on your bill to see the fixed cost in dollars. Then compare that same daily rate across a couple of retailers — it varies, and on a modest bill it can matter more than the usage rate.
Usage and tariff type: where the timing trap hides
How your usage is priced depends on your tariff:
- Single (flat) rate — one price per kWh, any time of day.
- Time-of-Use (ToU) — different prices for peak, shoulder and off-peak. Peak is typically around 2–8pm (later in some states — confirm from your own bill). This is now common.
- Controlled load — a separate, cheaper rate for a dedicated circuit like an electric hot-water tank, usually heated overnight.
On a ToU plan, when you use power matters as much as how much. Running the dryer, dishwasher and aircon together at 5pm costs far more than the same loads at 11am or overnight. Many people are moved onto ToU without changing their habits — and the peak-rate lines quietly swell.
A federal Solar Sharer offer began on 1 July 2026, providing a free-power window (an 11am–2pm block, up to 24 kWh a day) through participating retailers on eligible opt-in plans. It needs a smart meter, and availability varies by retailer and state — confirm what's offered where you are before banking on it.
Demand charges: the line that surprises people
A demand charge bills you on your single highest spike of draw during the charging window, scaled up as if you ran at that rate all month. Switch on the oven, kettle, aircon and pool pump at the same moment and you can set a high "demand" reading that costs you for the whole period — even if your total kWh is modest.
If your bill has a demand line (look for charges in c/kW/day or $/kVA), spreading big appliances out rather than clustering them can cut it noticeably. Here's the honest catch: on a demand tariff, adding solar panels may barely move this line, because your peak draw often lands in the evening after the sun's gone. Chasing solar to beat a demand charge can disappoint — the better lever is load-shifting, and sometimes a battery, sized to your actual peak.
Feed-in credits: real, but smaller than people hope
If you export solar, you'll see a feed-in credit, typically in the range of around 3–10 c/kWh depending on your retailer and state. In most states the retailer sets this rate and it has trended down for years; Victoria, regional Queensland and Tasmania set a regulated minimum. Compare that to the 20–40+ c/kWh you'd otherwise pay to buy power, and the lesson is clear: self-consuming your solar (running appliances while the sun shines) is worth far more than exporting it.
A quick line-by-line checklist
| Line | What it is | What you control |
|---|---|---|
| Supply charge | Fixed daily connection fee | Retailer choice only |
| Usage (peak/off-peak) | c/kWh for energy used | How much, and when |
| Controlled load | Cheaper circuit (e.g. hot water) | Make sure you're on it if eligible |
| Demand | Your highest draw spike | Don't run big loads at once |
| Feed-in credit | Paid for exported solar | Self-consume more instead |
Grab your latest bill, find each of these, and convert the daily rates to dollars for the period. You'll often find the "expensive" line isn't the one you assumed — and the cheapest fix is free.
We don't sell panels, batteries or electricity plans — so our only job is to read your actual bill and tell you which line is really costing you, even when the honest answer is "your current setup is fine, leave it alone."
Want to know what actually pays for your place?
Get an independent, engineered read on your whole bill — solar, battery, tariff and the rebates you're really entitled to — for a small fixed fee. No system to sell, no sales call.
Start your audit — $100Figures in this guide are current at the date of publication and indicative only — rebate and certificate values change over time (federal battery certificates step down each January and July), and state schemes are amended often. Confirm the current numbers for your situation before you commit. This is general information, not personal financial advice.