Martin McDowell's Blog

Now I was not brilliant in maths but I am still hoping my calculations are at least approximately correct.

Shell is the most simple to calculate so lets start with them. I tried to calculate how many litres of diesel I had to use to get 100 airmiles.

I used the Petrolprices.com website for my postcode: http://www.petrolprices.com/members/?search=SA62+3PW

Shell Driver’s Club

Price here is irrelevant though as they give you 1 airmiles for 20 litres. The website does not specify for which kind of fuels so I presume it is irrelevant. That makes:

2000 litres of diesel for 100 airmiles

Tesco Clubcard

Its more complicated here. A litre of diesel is 1.029 pounds which will give you 1 clubcard point. Usually I will fill up my tank which is 60 litres -> about 62 points.  100 points give you 1 voucher pound so mathematically that would be 0.62 voucher points for 60 litres. That is 0.0103 voucher points per litre of diesel or 96.77 litres of diesel/1 voucher point.

Now, Airmiles give you 60 airmiles for 2.50 voucher points, so that is 4.17 voucher points for 100 airmiles. As 96.77 litres come to 1 voucher point, 4.17 voucher points (for 100 airmiles) come to 403.22 litres of diesel.

So about 400 litres of diesel for 100 airmiles

Conclusion

That makes Tesco’s savings scheme 5 times more economical. I do understand that some numbers are rounded and the calculation is not linear but it does show the huge difference in the schemes for airmiles. Also you get more airmiles with diesel and/or higher prices with Tesco than you do with Shell. If the prices would go down you would relatively do better with a scheme per litre of fuel than per pence spent, but the absolute difference is still very much in favour of Tesco Clubcard. Not to mention that you get more points with Tesco as you get them by buying anything at the shop, not just the fuel.

And y the way, I am not affiliated with any company mentioned here but I have used all. If my calculations are incorrect please inform me through my contact form.