BillFair

Methodology

Every number on BillFair is an estimate with stated inputs. This page sets out what goes into a comparison, what the price index measures, and what neither of them can tell you.

1. Where the plan data comes from

Retailers publish their market offers under the Australian Energy Regulator's Consumer Data Right rules. That data includes the plan name, the retailer, the states and distribution networks served, the usage rate, the daily supply charge, contract terms and eligibility conditions.

BillFair takes a snapshot of the published business electricity plans once a week. The current snapshot drives the comparison engine. Earlier snapshots are retained, because they are what allow us to compare this week's advertised rates with last week's. Plans marked as broker variants are excluded from everything shown to customers.

We do not estimate a missing rate. If a plan does not publish a usable unit price and supply charge, it is left out rather than filled in with a guess.

2. How a comparison is calculated

The comparison begins with your bill. We read the billing period, the total consumption and, where the bill shows it, the demand and time-of-use breakdown. Those figures let us cost each plan against the way your site is actually charged instead of a generic profile.

For a simple flat-rate plan, the estimated annual cost is:

annual cost = (annual usage in kWh × usage rate in $/kWh) + (daily supply charge × 365)

Where a bill supports it, demand charges, time-of-use rates and solar feed-in are applied on the same basis. The saving shown is the difference between that estimate on the plan you are on and the same estimate on an alternative. It is indicative: it assumes the usage on your bill repeats for a year and that the plan's published rates stay unchanged.

3. How offers are ranked

Plans are ranked by estimated annual cost, lowest first. Ranking does not consider referral fees, commercial relationships or which retailer is easiest to switch to. Your current retailer is included in the results even when an alternative is cheaper, and the best available offer is shown first whether or not we have a commercial relationship with that retailer.

4. The Business Electricity Price Index

The index is a state-by-state view of what business electricity plans advertise, built from the same weekly snapshots. For each state we report:

  • the median advertised usage rate, in cents per kWh, across business electricity plans in that state;
  • the lowest advertised usage rate;
  • the number of plans and retailers in the snapshot; and
  • the change from the previous snapshot, in percentage terms.

The median is used rather than the average because a handful of unusually high or low offers should not move the headline figure. The index is based on advertised usage rates, not on what any customer actually paid. Network charges are set by the distribution business and passed through by every retailer, so they are not part of the retail rate being compared.

The annual-cost column on the index page uses a stated assumption of 20,000 kWh a year to make offers of different shapes comparable. It is an illustration, not a claim about your site. A site that uses more or less will see a different annual cost, and a site on a demand or time-of-use tariff should use the bill comparison instead.

5. What the numbers do not include

  • Your network tariff. Network charges are regulated and identical across retailers for the same connection, but they can dominate the total. The index compares the retail component only.
  • Conditional discounts. A plan may advertise a rate that depends on paying on time, direct debit, or another condition. The comparison uses the published rate; check the retailer's terms for conditions.
  • Fees and exit charges. Where a plan publishes an exit fee or another charge, it is shown in the comparison. The index does not model it.
  • GST and billing arrangements. Rates are compared as published. Confirm the GST treatment and billing terms in the retailer's offer.
  • Future price changes. A published rate can change. The snapshot date on every table tells you when the figure was taken.

6. Freshness and corrections

Plan data is refreshed weekly, and every table shows the date of the snapshot it came from. If a plan changes mid-week, the comparison reflects the last snapshot until the next one lands. The index is regenerated from the latest snapshot; the API and CSV download are available for anyone who wants to check the underlying figures.

If you believe a figure is wrong, email support@billfair.com.au with the plan and the figure you expected. We check corrections against the published source and fix the data, not the statement.