“
Can someone explain how the calculation in the Driving Down Costs example is worked out?
It has 15000 miles at 35 mpg costing 100.9p/l average fuel cost as £2160.
But I get:
15000/35 = 428 gallons
428*4.54 = 1943 l
1945* 1.009 = total fuel cost of £1960 ????
Then using cheap petrol (96.5p) the saving on the above is £83 not £270 as shown in the table.
Originally posted by LosEndos
”
I dunno what you're talking about, but on those figures it works out like this
15,000/35 = 428,5
428.5 x 4.546 = 1948 l
1948 x 1.06 = £2065 @ £1.06 per litre
1948 x 1.009 = £1965 @ £1.009 per litre
1948 x 0.965 = £1880 @ 96.5 p per litre (where do you get petrol that price these days?)
Which is almost what you got but just a little bit more accurate, I rounded to the nearest pound.
Ok, I see you're on about this bit....
follow this link
For a sample ten postcodes when the average price within a 5 mile radius was 100.9p, the average highest price was 106p and the average cheapest price 96.5p.
Following all the mechanisms above can save you cash. For someone who drives 15,000 miles a year averaging 35 miles per gallon (12.4 Km/litre), just buying petrol at the average UK cost in November 2007 is £2,160, yet buying at the average cheapest petrol station in any area would save more than £200. Of course prices change over time but the gap between the average price and the cheapest is pretty constant. Buying the petrol on a cashback card and improving your driving could save you a further £200.
To work out the initial rough cost of running your car, the VCA's (Vehicle Certification Agency) has a rough
fuel cost calculator (it's best for new cars) which will work out roughly how much it'll cost you to run your car over the course of a year.
Fuel Cost Cutting (as at November 07)
Annual Mileage, annual cost (1), Using cheapest fuel (2), cashback card saving (3), driving efficiently (4), Total Saving.
5,000 miles £720 £630 £615 £535 £185
10,000 miles £1440 £1260 £1230 £1070 £370
15,000 miles £2160 £1890 £1845 £1605 £555
I agree the figures are incorrect, if the avg fuel price in the area is 100.9p/l then the avg fuel cost should be £1965 not £2160 even using the most expensive petrol the cost would be £2065.
The differeence between the avg price and the cheapest price is £85
The difference between the expensive price and the cheapest price is £185
Then you add on 1p per litre clubcard savings = £20
Then you add a further saving of 15% by using a light foot and increasing your mpg
35mpg + 15% = 40.25mpg
15000/40.25 = 372
372 x 4.546 = 1694
1694 x .965 = £1635 saving £245
Total saving = 245 + 20 + 85 = £350
*and even that's not accurate because if you have a light foot you are no longer going to save £85 on the fuel difference, but I'm not going to work that out.