One Bill Isn't the Whole Story. Here's How We Estimate Your Annual Usage

Energy comparison accuracy is something nobody talks about honestly. Comparison sites show you a saving figure and present it as fact. They don't explain what assumptions produced it, how variable that figure might be, or in what circumstances their methodology fails.

We're going to explain ours. Including where it's less accurate and why.

What Every Comparison Tool Assumes (And Doesn't Tell You)

Standard comparison tools, every major Australian energy comparison site, compare plans using one of two approaches.

Approach one: You enter your usage The tool asks for your average quarterly kWh consumption or annual usage. You either know this or you guess. Most people guess, because most people don't track their kWh usage. The comparison is only as accurate as the number you enter.

Approach two: Postcode with average assumption The tool takes your postcode and applies a national or regional average consumption figure. The most common figure used in Australian comparison tools is 3,900 kWh per year for a single-rate household. If your household uses 7,500 kWh per year (common with ducted reverse-cycle air conditioning), the comparison is wildly underestimating your usage. If you use 2,200 kWh (small apartment, minimal heating and cooling), it's overestimating.

Neither approach uses your actual bill.

What We Do Differently

We read your bill. With your permission, you upload a photo or PDF. Our OCR engine extracts the actual data from the document.

Here's what we extract and use:

| Data point | Where we get it | Why it matters | |---|---|---| | Billing period (days) | Bill header or summary | Normalises consumption to a daily average | | Total kWh consumed | Usage section | Your real consumption, not an estimate | | Usage rate (c/kWh) | Charges section | Your current rate for comparison baseline | | Supply charge (c/day) | Charges section | Fixed cost component of current plan | | Tariff type | Rate structure section | Determines which comparison methodology applies | | Peak/shoulder/off-peak split | Usage breakdown (if TOU) | Required for accurate TOU comparison | | Solar export kWh | Solar section (if applicable) | Feed-in tariff component | | Feed-in tariff rate | Solar section | Current FiT for solar comparison |

This data set allows us to establish your actual current plan cost for the billing period. Not an estimate, but a calculation from real numbers.

The Hard Part: Annual Estimation From a Single Bill

Here's where we need to be honest about limitations.

A single bill covers one billing period, typically 60–92 days. That period may be your peak summer consumption quarter, your quietest shoulder quarter, or anything in between. Multiplying one quarter's consumption by four and calling it your annual usage is wrong for most households. It's most wrong for households with significant seasonal variation.

Our approach is seasonal extrapolation. We take your billing period consumption and apply seasonal adjustment factors to estimate what your usage looks like across a full year.

How the seasonal adjustment works: We know, from real bill data across Australian climate zones, approximately what proportion of annual usage falls in each quarter for different household types. A Queensland household with ducted reverse-cycle in a January billing period is likely to be near their annual consumption peak. We apply an adjustment that scales their January usage down to reflect that it's a high-consumption outlier in the annual pattern, not a representative average.

Where this is accurate: The seasonal extrapolation is most accurate for:

• Households with significant space heating/cooling (the seasonal curve is well-defined)
• Bills that are clearly seasonal peak or trough (the adjustment is most important and most reliable at extremes)
• States with clear seasonal energy demand patterns (most of eastern Australia)

Where this is less accurate: The seasonal extrapolation is least accurate for:

• Households with very flat year-round usage (small apartments with no heating/cooling)
• Households in mild climates where seasonal variation is minimal
• Bills from shoulder seasons (spring/autumn) where the adjustment factor is smaller and the baseline is more representative anyway

Our accuracy confidence ranges: We display an accuracy confidence on every result.

• ±0–5%: Actual read bill, full-year data available, or multiple bills uploaded
• ±5–10%: Seasonal peak or trough bill from a high-variation household in a climate zone with clear seasonal patterns
• ±10–20%: Single bill from a shoulder period or a household with moderate seasonal variation
• ±20–25%: Single bill from a household where we have limited information about seasonal variation

These ranges reflect our uncertainty, not a failure. A comparison showing a $400 saving with ±15% accuracy means the real saving is likely between $340 and $460. That's still meaningful information.

How Our Accuracy Compares

The alternative isn't a more accurate comparison tool. It's a less accurate one.

A postcode-based comparison using a 3,900 kWh annual assumption for a household that actually uses 7,500 kWh produces a saving figure that can be off by hundreds of dollars, in either direction. The error isn't bounded or disclosed. The comparison just shows you a number and implies it's correct.

Our seasonal extrapolation with disclosed accuracy ranges is more honest and typically more accurate than an undisclosed assumption-based comparison, even at the low end of our confidence range.

The only more accurate comparison is one with your full 12-month bill history or smart meter data. If you have access to your smart meter data through your retailer's app or portal, uploading that data alongside your bill gives us a better annual consumption estimate. More bills = better accuracy.

What We Don't Do

We don't recommend the cheapest plan regardless of fit. A plan that's technically cheapest based on usage assumptions but requires a direct debit you can't reliably maintain, or has a tariff structure that penalises how you actually live, isn't the right recommendation. We show you the options and let you choose.

We don't claim precision we don't have. Every comparison result comes with an accuracy range. If the accuracy is low for any reason, we show that. We'd rather tell you the saving is approximately $200–350 than pretend it's exactly $274.

We don't show plans we can't verify. Every plan in our comparison is pulled from the CDR feed, the same government-maintained data that powers Energy Made Easy. If a plan isn't in the CDR, we don't show it. This means we don't show you plans we can't verify are real, current, and available in your area.

The Bottom Line on Accuracy

A comparison from your actual bill, seasonally adjusted, with disclosed confidence ranges, against live CDR data, is the most accurate residential energy comparison currently available in Australia.

It is not perfect. No single-bill comparison can be. But it is dramatically more useful than a postcode entry producing a plan list based on a usage figure that has nothing to do with your household.

Upload your bill. Read the confidence range we show you. Understand that the number is an estimate with a margin. And then decide whether the saving, even at the low end of the confidence range, is worth ten minutes of your time to switch.

For most households, it is.

Fix Your Bill's OCR engine and seasonal extrapolation methodology have been developed and calibrated against real Australian residential bill data. Accuracy confidence ranges are calculated per-comparison based on bill quality, seasonal position, and tariff complexity.