UK petrol and diesel prices: judge the cost of a local fill-up

A difference of 5p per litre changes the cost of a 50-litre fill-up by £2.50. That makes the price on a nearby pump worth comparing with the UK weekly average, but the national figure cannot tell you what every local station should charge. Check the date of the government figure and compare petrol with petrol or diesel with diesel.

Check the date before comparing prices

The Department for Energy Security and Net Zero publishes weekly UK road fuel prices. Its petrol and diesel averages provide a national benchmark for a local pump price. The source information available confirms the series but does not include its latest dated numerical readings, so no current average is quoted here.

A useful comparison starts with the date attached to the weekly figures. A pump price seen today and an average from an earlier week describe different moments. Prices may have moved between them. Record the weekly date, the relevant fuel average and the local pump price before calculating the gap.

The units matter too. Pump signs commonly show pence per litre. If one price is written in pounds, convert it before subtracting: £1.45 per litre is 145p per litre. Compare the same fuel grade throughout, since a standard petrol average is not a direct benchmark for a premium petrol price.

Turn a per-litre gap into a tank cost

The calculation is straightforward: subtract the weekly average from the local price, then multiply the difference by the litres you expect to buy. A positive result means the local fill-up costs more than a fill-up at the benchmark price; a negative result means it costs less.

The table below is an illustration, not a report of current prices. It shows how two possible pump prices affect a 50-litre purchase.

For a smaller 30-litre purchase, the same 5p-per-litre gap would be £1.50. For 60 litres, it would be £3.00. Use the amount you will actually put in the tank rather than the vehicle’s stated tank capacity if you are only topping up.

The same arithmetic applies when a dated government average is available. If a station is 4p per litre above the relevant weekly average, buying 40 litres adds £1.60 relative to that benchmark. That example describes a price difference, not a saving you can necessarily obtain nearby.

Why the UK average is a benchmark, not a local promise

A UK average combines prices across many forecourts. Individual stations can sit above or below it. The national figure does not identify the cheapest station on your route, guarantee that a nearby pump matches the average or explain why a particular forecourt charges more.

For a fill-up decision, compare the dated average with the pump price, then look at other stations you could reasonably use. A cheaper sign may save little once an extra journey is considered. Your most useful next check is the current price for the same fuel at an accessible station, alongside the date of the latest government weekly reading.

Source: UK Department for Energy Security and Net Zero