The mileage figure on a vehicle’s brochure comes from a controlled lab test. The mileage you actually get depends on how, where and in what condition you drive — and the gap between the two can be significant.
The tank-to-tank method
- Fill your tank completely and note the odometer reading (or reset the trip meter).
- Drive normally until the tank is nearly empty.
- Fill up again, completely, and note exactly how many litres it took.
- Divide the distance travelled by the litres used — that’s your real mileage in km/l.
Repeating this over two or three fill-ups and averaging the results gives a more reliable figure than a single tank, since traffic and routes vary day to day.
What lowers real-world mileage
- Stop-start city traffic, versus steady highway cruising
- Underinflated tyres, which increase rolling resistance
- Continuous air-conditioning use, especially at low speeds
- Aggressive acceleration and hard braking, which can cost 15–20% mileage
- Extra weight in the vehicle
Put your number to use
Once you know your real km/l, you can budget any trip accurately. Enter distance and fuel used into the Mileage Calculator, then use that figure in the Fuel Cost Calculator to estimate what your next drive will cost at current fuel prices.