UK Fuel Price Finder — How It Works

Summary

The UK Fuel Price Finder shows live forecourt prices from 14 major fuel retailers on an interactive map. It uses data published under the CMA (Competition and Markets Authority) Fuel Finder scheme, which requires large retailers to make their prices publicly available in a machine-readable format.

You search by postcode or use your device’s location, choose a fuel type, and the map shows nearby stations colour-coded from green (cheapest) to red (most expensive). Select a station to see the exact fill cost for your tank size and how much you’d save compared to the priciest station nearby.

The CMA Fuel Finder scheme

In 2023, the CMA concluded its Road Fuel Market Study and found that drivers lacked easy access to real-time price comparison. The CMA issued an open letter requiring 14 major fuel retailers — who together account for around 75% of UK fuel sales — to publish live price feeds in a common JSON format.

Each retailer publishes a feed containing every forecourt they operate, with:

• Site ID and brand name
• Address and postcode
• GPS coordinates (latitude and longitude)
• Prices for each fuel type available (in pence per litre)

The 14 retailers are: Ascona, Asda, BP, Esso, JET, Karan Retail, Morrisons, Moto, Motor Fuel Group (MFG), Rontec, Sainsbury’s, SGN, Shell, and Tesco.

Prices are updated at least daily, with most retailers updating whenever pump prices change.

Fuel types explained

UK forecourts sell several grades of fuel, identified by industry codes:

Most drivers use E10 (unleaded) or B7 (diesel). The Fuel Price Finder defaults to E10 as it’s the most commonly purchased fuel.

How savings are calculated

The per-fill savings calculation is straightforward:

savings = (expensive price − cheapest price) × tank size ÷ 100

The result is in pounds. For example:

Cheapest station: Asda at 131.9p/L (E10)

Costliest nearby: Shell at 142.9p/L (E10)

Tank size: 40 litres

Savings: (142.9 − 131.9) × 40 ÷ 100 = £4.40 per fill

Over 30 fills per year, that’s £132 saved by choosing the cheapest station.

How the map works

1. Data aggregation — our server fetches all 14 retailer feeds in parallel, normalises them into a common format, and filters to stations within your search radius (default 10km).

2. Colour coding — each station pin is coloured on a green-to-red scale based on its price percentile among visible stations. The cheapest station is pure green; the most expensive is pure red.

3. Edge caching — results are cached for 30 minutes at the edge (via Cloudflare), so nearby searches are fast and don’t overload retailer feeds.

Tips for saving on fuel

• Supermarkets are usually cheapest — Asda, Sainsbury’s, Tesco, and Morrisons consistently undercut branded stations by 3–8p/L.
• Avoid motorway services — Moto and other motorway operators are typically 15–25p/L above average.
• Fill up, don’t top up — a full tank means fewer stops. The finder’s per-fill cost helps you compare the actual pound-note difference.
• E10 vs E5 — unless your car specifically requires premium, E10 is the better-value choice. The marginal efficiency gain from E5’s higher octane rarely offsets the 8–12p/L price premium for most engines.
• Check before long journeys — prices can vary by 20p/L within a few miles, especially near motorways.

Data freshness

Retailer feeds are fetched live on each search (with 30-minute edge caching). Some feeds may temporarily be unavailable — the finder shows how many of the 14 feeds responded successfully. If a retailer’s feed is down, their stations simply won’t appear until the feed recovers.