Use this data

Each headline average is the mean pump price across every station that has reported that fuel within the last 5 days, recomputed roughly every 30 minutes. We use a 5-day window because a “UK average” is a ranking-class claim: it should reflect what stations are charging now, not a fortnight ago.

Before averaging we drop implausible prices (anything outside a sane pence-per-litre band) and suppress junk readings — frozen or mistyped prices that would otherwise skew the mean.

Alongside the average we publish the spread over the same 5-day window: the 5th and 95th percentiles, plus the outright minimum and maximum. Percentiles resist the odd rogue price far better than min/max alone, so the 5th–95th band is the honest “most drivers pay between X and Y.”

Regional numbers roll every station up to one of the twelve UK statistical regions (ITL1: the nine English regions plus Scotland, Wales and Northern Ireland) by the leading letters of its postcode. Several postcode areas straddle a boundary; each is assigned to the region holding the plurality of its population.

The best-known call is Shrewsbury (SY), which we place in the West Midlands even though it borders mid-Wales. Note that our nation-level rankings elsewhere split SY the other way, into Wales — a nation split and a region split optimise for different things, and both are deliberate.

The motorway premium is the difference between the average price at motorway-services forecourts and the average everywhere else, over the same 5-day window.

The history chart and the CSV stitch two datasets. For the years before Pennr’s own archive begins, we use DESNZ weekly road fuel prices — the government’s national petrol and diesel series going back to 2003, published under the Open Government Licence v3.0. From the point our own daily data starts, we switch to that.

We never level-adjust: DESNZ points keep their published values and Pennr points keep theirs, even though the two national bases sit a few pence apart. The seam is visible — the CSV’s source column labels every row — and we never compute a day, week or month change across it, because that step would show up as a phantom “surge” that never happened at the pump.

Every timestamp is a report time, not a pump time. Every UK forecourt selling petrol or diesel to the public must report price changes within 30 minutes. What we can show is when a station reported — not the exact minute the pump price actually changed. We word it that way everywhere: “stations reported…,” never “prices changed….”

We show the tax you can verify — fuel duty (a flat statutory rate) and VAT (20%) — but we don’t split out the wholesale cost or the retailer’s margin, because the feed doesn’t contain that data and we won’t estimate a number we can’t stand behind.

We also don’t cover LPG or EV charging: neither is part of the statutory Fuel Finder feed, so there is nothing honest for us to report.