How OTW works
The cheapest fuel on your route isn't always the cheapest price. A station 3¢/L cheaper that's 8 km off the highway can lose you money. OTW works out which stop is actually worth taking.
Three steps
Tell us your car
Year, make and model. We look up its fuel consumption and tank size.
Say how much fuel you have
Slide to roughly where your gauge sits. We work out how far you can go.
Enter your trip
We find stations near your route and rank them by estimated fuel savings.
Why the cheapest station can cost you money
Here is an illustrative Melbourne to Sydney example, filling 40 litres:
| Station | Price | Detour | You actually save |
|---|---|---|---|
| Cheapest price | $2.345/L | 12.5 km · 15 min | $5.38 |
| Best value | $2.349/L | 2.3 km · 3 min | $7.62 |
The cheaper station is 0.4¢/L less — and leaves you $2.24 worse off after estimated detour fuel cost. Its 15-minute detour is also 12 minutes longer than the best-value stop's.
How we work out your range
Official fuel figures are measured in a laboratory. OTW increases the published consumption figure by 20% as a planning allowance; actual consumption may be higher or lower.
fuel on board = tank size × how full it is usable fuel = fuel on board − reserve real usage = lab figure × 1.20 range = usable fuel ÷ real usage × 100
The reserve is 5 litres, or 10% of your tank, whichever is larger. We hold it back rather than planning to use every litre. Keep your own safety margin, especially on remote roads.
How we rank the stops
Every station near your route is scored on what you'd save against the average price along that route, minus the fuel burned reaching it.
litres to fill = tank size − fuel on board saving on fuel = (route average − station price) × litres to fill detour cost = (round-trip detour km ÷ 100) × real usage × station price what you save = saving on fuel − detour cost
You can sort three ways: Best value (estimated fuel saving), Cheapest (lowest price, whatever the detour), and Least detour (barely off your route). Detour distance is a straight-line estimate, doubled for the return to the route. Detour time is shown separately and is not given a dollar value in the saving. Every stop shows its working.
Where the data comes from
- Fuel prices come from the state government fuel-price feeds across Australia: FuelCheck NSW/ACT, FuelCheck Tasmania, Fair Fuel Victoria (Servo Saver), Queensland fuel-price reporting, FuelWatch WA, SAFPIS in SA and MyFuel NT. Each price shows its report time. Prices 24–48 hours old are marked stale and excluded from recommendations; prices older than 48 hours are hidden.
- Which cars matter comes from BITRE's Road vehicles Australia — a census of what is actually registered and on the road here, rather than what sold well.
- Fuel consumption comes from the Australian Government's Green Vehicle Guide, used under licence. Where several figures were published for an engine and year, OTW takes their median and then applies its 20% planning allowance. Tank capacities are OTW estimates compiled from manufacturer specifications.
What we don't know
We would rather tell you this than have you find out on the road:
- The adjusted consumption and tank size are planning estimates. If we have your tank size wrong, enter the figure from your owner's manual and OTW will use that instead.
- Detour distance is measured straight-line to the station and back, not turn-by-turn. It will understate detours where the station is across a divided highway.
- Prices change through the day. We show you when each one was last updated so you can judge for yourself.
- Your real range depends on load, terrain, traffic, tyres and how you drive. The range is an estimate, not a guarantee.