How Petrol Australia Calculates Fuel Savings — Area Median, Effective Prices, Net Drive Cost

Every savings figure in Petrol Australia — on a station, the cheapest-in-view banner, a trip, or a comparison — uses the same method. Consistent numbers, no matter where you look.

The baseline: area median, not average

A "saving" only means something against a reference price. We use the median of the stations around you — the middle price when they're lined up cheapest to dearest.

We use the median (not the average) on purpose. One unusually high or low station drags an average around; the median ignores those outliers and reflects what most stations are actually charging.

Example. Eight nearby stations: 159, 161, 162, 163, 164, 165, 168, 209c. The average is pulled up to ~169c by the single 209c outlier. The median is 163.5c — closer to what you'll really pay. We compare against 163.5c.

Effective prices (your discount counts)

The baseline is built from effective prices — the pump price minus any discount program you're enrolled in (for example a 4c/L fuel docket). This keeps the comparison like-for-like: your discounted price is measured against everyone else's discounted price, not against undiscounted pump prices.

If discounts are turned off, the baseline is simply the pump prices.

Gross vs net saving

Gross saving = (baseline price − the price you pay) × your tank size, in dollars. This is the headline "Save $X / tank" figure.
Net saving = gross saving − the cost of the fuel burned driving to the station. Net saving only appears where driving distance matters (Station Compare and Route), because that's when the detour can eat the saving.

Example. Baseline 163.5c, station 154.0c, 50L tank → gross saving = (163.5 − 154.0) × 50 ÷ 100 = $4.75. If reaching it burns $1.20 of extra fuel, the net saving is $3.55.

Why two screens can show different numbers

The method is identical everywhere; only the set of stations in the baseline changes:

Station details / cheapest-in-view — the stations currently in your area or map view.
Route — the stations along your planned trip corridor.

Different areas, different medians — so the same station can show a slightly different saving on the map versus on a route. That's expected, and each screen tells you what it compared against (e.g. "vs area median (162.9c)").

What this means for you

A green "Saving" badge means the station beats the typical price near you.
"Worth the drive" (net saving) and "good price" (gross saving) are different questions — Station Compare and Route answer the first.