Question 1

Is it actually worth driving further for cheaper fuel?

Accepted Answer

Only sometimes. A forecourt a few pence cheaper per litre can still leave you worse off once you count the extra fuel burned driving there and back — especially for a small fill-up or a longer detour. This tool works out the real net saving using your car's economy and the actual driving distance, not just the price difference.

Question 2

How is the saving worked out?

Accepted Answer

We take the price difference across your fill-up size for the raw saving, then subtract the cost of the fuel you'd burn on the round trip at your car's real-world mpg (a haircut off the official combined figure, since real driving is usually 10–15% thirstier). What's left is the net saving — the number that actually matters.

Question 3

Why does it use real driving distance, not straight-line distance?

Accepted Answer

Straight-line distance understates how far you actually have to drive, especially in towns or where a river, motorway or one-way system is in the way. We look up the real driving route for the closest candidates so the fuel cost of getting there is accurate.

Question 4

What if I don't know my car's mpg?

Accepted Answer

Just enter your registration in the tool. Where we can resolve it — from the published economy figures for your exact model, or a fuel-type and engine-size estimate as a last resort — we pull the fuel type and mpg for you automatically. If we can't, you can enter the official combined mpg from your V5C or a spec sheet manually instead.

Question 5

Does this work for electric cars?

Accepted Answer

Not for a forecourt comparison — EVs don't fill up with petrol or diesel, so there's no pump saving to weigh against a longer drive. Public charging prices vary a lot by network and charging speed, which is a different comparison to this tool.

Is it worth the drive for cheaper fuel?

Why net saving matters

Frequently asked questions

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