Fuel Cost Calculator

How to use Fuel Cost Calculator

1. 1
   Enter the distance. One way — tick the return option rather than doubling it yourself.
2. 2
   Enter your consumption. From the trip computer if you have one; the official figure is usually optimistic.
3. 3
   Add the pump price. And how many people are sharing, if you are splitting it.

About calculating fuel cost

Fuel cost is one of the few household calculations where the arithmetic is easy and the input is the problem. Consumption figures published by manufacturers come from a standardised laboratory cycle, and while the current WLTP test is considerably more realistic than the NEDC one it replaced, real-world use still runs above it — commonly by ten to twenty-five percent, and much more for short urban journeys where the engine spends most of its time below operating temperature. A trip computer reading averaged over a few tanks is a far better input than the brochure. The second thing worth knowing is that consumption is not linear in speed. Aerodynamic drag rises with the square of velocity, so above roughly 80 km/h each additional increment costs disproportionately more, and the difference between 100 and 120 km/h on a long journey is usually fifteen to twenty percent of the fuel for a small saving in time. Below that range the picture inverts, because a cold engine and low-gear running are inefficient regardless of speed. Finally, fuel is only the marginal visible cost. Tyres, servicing intervals, and the depreciation attributable to distance typically at least double the true cost per kilometre.

Frequently asked questions