How we calculate our fuel price figures
Every figure on our town, retailer and forecourt pages comes from prices that forecourts report themselves. This page explains where they come from, which ones we count, and how averages, cheapest prices, rankings and trends are worked out, so you can judge what each number means.
database Where the prices come from
Petrol and diesel prices come from the UK Government's Fuel Finder scheme, which forecourts are required to report their prices to. FillRadar reads the full set about every 30 minutes. The data is published under the Open Government Licence v3.0. FillRadar is an independent service and is not affiliated with or endorsed by the Department for Energy Security and Net Zero.
We show prices as forecourts report them. We do not adjust, estimate or fill in missing prices.
schedule What "price reported 7 hours ago" means
Each price carries the time the forecourt says it took effect, which is when the price last changed. It is not the last time anyone checked it. A price that has not changed for a week is not out of date: it means the forecourt has kept the same price. Forecourts are required to report changes, so we show every reported price as it stands.
"Prices read 20 minutes ago" under a page heading is different: it is when FillRadar last fetched the whole set.
verified_user Which forecourts and prices we count
- Open forecourts only. A forecourt the feed marks as temporarily or permanently closed is left out of every figure.
- Believable prices only. A price below 80p or above 400p a litre is treated as a reporting error and left out.
- Grades. Unleaded is E10 petrol, super unleaded is E5, diesel is B7, and premium diesel is the branded high-performance diesel some forecourts sell. HVO and B10 are sold at few forecourts, so they have one UK-wide page each instead of a column per town.
location_city What a "town" covers
Every forecourt's address ends with its town and postcode. We group forecourts by that town name and region, put the town's centre at the middle of its forecourts, and draw a circle around it that covers most of them: between 3.5 and 6 miles, measured in a straight line. Fifty of the largest towns and cities have a centre and radius we set by hand, from 4 miles for smaller cities to 12 for London.
A town page counts every open forecourt inside its circle, so it can include neighbouring villages and suburbs. A town gets a page when at least five forecourts fall inside. A town's region comes from its postcode area, which occasionally puts a border town in the neighbouring region.
functions How each figure is worked out
- Average: the plain average of the prices of every counted forecourt that sells that grade. Each forecourt counts once, whatever its size.
- Cheapest and dearest: the lowest and highest counted price. The cheapest lists are sorted by price, then by distance from the centre.
- Spread: the gap between the cheapest and dearest price in the town. It is not the saving on any particular journey.
- Above or below the UK average: the town or forecourt price minus the average of every counted forecourt in the UK for that grade.
- Forecourt ranking: on a forecourt page, "cheapest of 18 within 5 miles" compares its price with every counted forecourt within 5 miles that sells the same grade.
- Distances: straight-line distances, not driving distances.
show_chart Price trends
Town and retailer charts show one average per day for the last 14 days. Past days come from our daily price archive, a copy of every forecourt's price taken at 22:30 each evening; the last point is today's live figure. A forecourt page's chart shows the price that stood at the end of each day, from the price changes the forecourt has reported.
local_gas_station Retailer figures
Forecourts are grouped into retailers (Tesco, Asda, Sainsbury's, Morrisons, Shell and BP) by the brand name in the feed. Supermarket forecourts are matched by a name that starts with the brand; Shell and BP are matched anywhere in the name, so their figures include dealer-run forecourts that trade under the brand. A retailer's average is the plain average of its counted forecourts across the UK.
rule Limits
- A forecourt can change its price between our updates, and a reported price can be wrong. Always check the price at the pump.
- Opening hours are not published in the scheme, so we do not show them.
- LPG, EV charging and boat fuel prices come from other sources and are explained on the About & data sources page.
Found a figure that looks wrong? Tell us at support@fillradar.co.uk.