Is It Worth Driving Further for Cheaper Fuel?

It is tempting to drive across town for fuel that is a few pence a litre cheaper. But the trip itself burns fuel. Here is how to tell whether it pays.

The break-even sum

1. Work out the cost of the detour. Extra miles × cost per mile. For cost per mile see cost per mile for petrol vs diesel.
2. Divide by the litres you are buying.
3. The answer is the minimum saving in pence a litre you need to break even.

Worked example

You normally pay 174p. A cheaper station is 10 miles away, so a 20-mile round trip. Your car does 40 mpg on petrol.

• Fuel used: 20 ÷ 40 = 0.5 gallons = 2.27 litres
• Cost of the trip: 2.27 × 1.7407 = about £3.96

Now see how many litres you are buying:

So if the cheaper station is only 5p a litre less, driving 20 miles round trip to buy 40 litres loses you about £2. If it is 15p less, you gain about £2 (40 litres × 15p = £6, minus £3.96).

When it is worth it

• The saving is large, such as 15p or more a litre
• You are buying a lot of fuel, a full tank
• The station is on your way or only a short detour

When it is not

• The saving is a few pence
• You only need a small top-up
• The detour adds many extra miles, or you would sit in traffic

Do not forget your time and the cost of wear on the car. If it takes 30 minutes to save £2, it is probably not worth it.

Let the ranking do the sum

Our search ranks stations by true cost. It adds the price of filling up to the cost of driving there and back, using your car's mpg and how many litres you plan to buy. Set your car in My Car, search your postcode, and the best option floats to the top, which is often not the lowest pump price.

The best saving of all

The cheapest fuel is on your normal route. If one station on your commute is consistently good value, save it and use it. For more ideas, read 12 ways to cut your fuel bill.

Search your postcode and compare by true cost.

Compare prices in your city: London, Birmingham, Manchester, Leeds, Glasgow, or see petrol prices by city.