Postcode vs Bill: Why the Best Electricity Plan for Your Postcode Isn't the Best Plan for You

There are two ways to compare electricity plans.

The first way: enter your postcode. See a list of plans sorted by estimated annual cost, with a generic usage assumption buried somewhere in the fine print. Pick one.

The second way: upload your bill. The comparison reads your actual usage, your actual current rates, your actual tariff structure. The saving figure is calculated against your household, not a hypothetical average one.

Every major energy comparison site in Australia uses the first method. We use the second. Here's why that matters, and when the difference is large enough to change which plan you should be on.

What Postcode Comparison Actually Tells You

A postcode comparison tells you: which plan would be cheapest for a hypothetical household with average usage in your postcode, using a standard rate schedule.

This is useful information. It's not the same as "which plan is cheapest for my household."

The gap between these two questions depends on how different your household is from the average assumption.

If you use roughly 3,900 kWh per year (the common default assumption), are on a flat rate, have no solar, and your bills are fairly consistent throughout the year, a postcode comparison is reasonably accurate for you. The assumption is close to your reality.

If you use significantly more or less than the assumption, the comparison diverges. Plans are priced with volume-sensitive structures. The supply charge is fixed regardless of how much you use, while the usage rate applies per kWh. A household using double the assumed volume would be significantly better served by a plan with a lower usage rate and a higher supply charge than the comparison tool recommends, because the usage rate savings at high volume outweigh the supply charge premium.

If you're on time-of-use tariffs, a flat-rate comparison is almost meaningless. Your actual cost on a TOU plan depends on when you use electricity, a figure the postcode comparison doesn't have and can't estimate.

If you have solar, the comparison needs to account for both import and export. A postcode comparison that ignores your solar export volume is comparing only half your bill.

The Three Scenarios Where Postcode Comparison Fails

Scenario One: High-usage household recommended a low-usage plan

A household using 8,000+ kWh per year (ducted air conditioning, electric hot water, home office, family) enters their postcode. The tool's assumption is 3,900 kWh. It recommends a plan with a low usage rate and a high supply charge, optimal for moderate users.

This plan is cheaper than average for the 3,900 kWh assumption. For the 8,000 kWh household, the supply charge premium is overwhelmed by the usage rate, which is why that plan appeared cheap in the first place. The comparison tool recommended the wrong plan.

With a bill upload, the actual consumption is known. The comparison is run against 8,000 kWh. The plans optimised for high-usage households appear at the top. The recommendation is correct.

Scenario Two: TOU customer compared on flat rates

A household on a time-of-use tariff runs heavily in the evening (cooking, TV, heating), which falls in the peak pricing period. The postcode comparison, unaware of this pattern, shows TOU plans as potentially attractive based on their headline peak/off-peak rates, without accounting for how this household's specific timing interacts with those rates.

The result: an apparently competitive TOU plan that, given this household's peak-heavy usage, turns out to be expensive. The comparison should have recommended a flat-rate plan that insulates the household from peak pricing, but the postcode tool couldn't know that.

With a bill upload, the actual TOU consumption split is extracted. The comparison accounts for peak-heavy usage. The flat-rate recommendation is correct.

Scenario Three: Solar household optimised for FiT, wrong on usage rate

A solar household with a 6.6kW system sees a plan advertised with an attractive 10 c/kWh feed-in tariff. The postcode comparison shows it as the clear best option.

But this household imports 4,000 kWh per year from the grid and only exports 2,000 kWh. The high usage rate on the high-FiT plan, 36 c/kWh, costs $1,440 in import charges annually. The 10 c/kWh FiT earns them $200 in export credits. Net import cost: $1,240.

A competing plan with a 6 c/kWh FiT and a 26 c/kWh usage rate costs $1,040 in import charges and earns $120 in export credits. Net import cost: $920.

The high-FiT plan costs $320 more per year for this specific household because of their import/export ratio. The postcode comparison, which didn't know this ratio, recommended the wrong plan.

The Postcode Comparison Has Its Place

This isn't an argument that postcode comparison is useless. For some households, it's perfectly adequate. If your usage is close to average, your tariff is simple flat rate, and you just want a rough sense of which providers are expensive versus cheap in your area, a postcode comparison gives you that.

The problem is that the households most in need of accurate comparison (high-usage households paying the biggest loyalty penalties, TOU customers on the wrong tariff structure, solar households with complex billing) are the households most poorly served by the postcode approach.

These are also the households with the most to save. A 10% error on an average bill is $50. A 10% error on a high-usage household's bill is $150. The stakes of an inaccurate comparison grow with usage volume.

What a Bill-Based Comparison Requires From You

One bill. A photo from your phone or a PDF from your email. That's it.

We don't ask you to enter your quarterly kWh. We don't ask you to figure out your tariff type. We don't ask you to dig through your account portal for 12 months of data. We read the bill.

In 40 seconds, we know more about your household's energy situation than any postcode-based comparison can determine from a full session.

The comparison is more accurate. The recommendation is more relevant. The saving figure is a real number for your household, not a median estimate for your suburb.

Fix Your Bill uses CDR data for plan pricing. All comparisons are based on data extracted from your uploaded bill combined with live plan data for your network area. Accuracy confidence is shown on every result.