What Is B7 Diesel?
B7 is the standard diesel fuel sold at UK filling stations, containing up to 7% renewable biodiesel. The average price today is 188.1p per litre across 2,487 stations.
B7 Diesel Explained
B7 diesel is a blend of conventional petroleum diesel and up to 7% FAME (Fatty Acid Methyl Esters) biodiesel. The biodiesel component is produced from renewable sources such as rapeseed oil, soybean oil, and used cooking oil.
The UK has required all standard diesel to contain up to 7% biodiesel since 2011, as part of the Renewable Transport Fuel Obligation (RTFO). This helps reduce the carbon intensity of road transport — B7 produces lower lifecycle CO₂ emissions than pure petroleum diesel.
B7 Diesel vs Petrol — Cost Comparison
| B7 Diesel | E10 Unleaded | |
|---|---|---|
| Average price | 188.1p | 156.7p |
| Energy per litre | ~36 MJ | ~32 MJ |
| Typical MPG | 50–70 mpg | 40–55 mpg |
| Cost per mile (approx.) | 14.3p | 15.2p |
While diesel is more expensive at the pump, diesel engines extract more energy per litre, so the cost per mile is often similar to — or even lower than — petrol for higher-mileage drivers.
B7 vs Premium Diesel
Premium diesel products (such as Shell V-Power Diesel, BP Ultimate Diesel, and Esso Synergy Supreme+ Diesel) contain cleaning additives designed to prevent injector deposits and improve combustion. They may also have a different cetane rating.
Right now, premium diesel averages 208.2p compared to 188.1p for standard B7 — a premium of 20.0p per litre.
For most diesel cars, standard B7 is perfectly adequate. Premium diesel may benefit vehicles with high mileage or those used for frequent short trips where injector deposits can build up faster. Learn more on our premium diesel guide.
Cheapest B7 Diesel in the UK Today
Updated 4 May 2026. Prices from official retailer feeds.
| # | Brand | Address | Price | £/Litre |
|---|---|---|---|---|
| 1 | MIDWAY SERVICE STATION | POST OFFICE, 351, SLIGO ROAD, LETTERBREEN, ENNISKILLEN, BT74 9FH, ENNISKILLEN | 123.9p | £1.24 |
| 2 | DERRYCHRIER SERVICES LTD | 772, FEENY ROAD, DUNGIVEN, LONDONDERRY, BT47 4TB, LONDONDERRY | 133.9p | £1.34 |
| 3 | TEST FORECOURT 1 8APR | CROSSLEY STONE HOUSE, 20, CROSSLEY STONE, RUGELEY, WS15 2DQ, RUGELEY | 136.0p | £1.36 |
| 4 | JET | FOUR WINDS SERVICE STATION, EAST HECKINGTON, BOSTON, PE20 3QF, BOSTON | 137.9p | £1.38 |
| 5 | VALERO | 6 BILLACOMBE ROAD, POMPHLETT, POMPHLETT | 138.7p | £1.39 |
| 6 | R & T MAYBURY HILL LTD | MAYBURY HILL SERVICE STATION, MAYBURY HILL, WOKING, GU22 8AA, WOKING | 138.9p | £1.39 |
| 7 | BEEL PROPERTY LTD | KNOWLE GARAGE, KNOWLE, BRAUNTON, DEVON | 138.9p | £1.39 |
| 8 | WILF NOBLE BUILDING SUPPLIES LTD | RUSWARP SERVICE STATION, SNEATON LANE, RUSWARP, WHITBY, YO22 5HL, WHITBY | 139.9p | £1.40 |
| 9 | DUNCHURCH SERVICE STATION | DUNCHURCH SERVICE STATION, COVENTRY ROAD, DUNCHURCH, RUGBY, CV22 6RA, RUGBY | 139.9p | £1.40 |
| 10 | BP | 176 BO'NESS ROAD, GRANGEMOUTH, GRANGEMOUTH | 141.9p | £1.42 |
Frequently Asked Questions
What does B7 mean in diesel?
B7 stands for diesel blended with up to 7% biodiesel (FAME — Fatty Acid Methyl Esters). The 'B' is for biodiesel and '7' represents the maximum percentage. All standard diesel sold in the UK since 2011 has been B7.
Is B7 diesel the same as regular diesel?
Yes. B7 is simply the technical name for the standard diesel you buy at any UK filling station. When a pump says 'Diesel', it's B7. Premium diesel products like Shell V-Power Diesel or BP Ultimate Diesel are different — they contain additives and may have a different biodiesel blend.
Is diesel more expensive than petrol?
Currently, standard B7 diesel averages 188.1p per litre, while E10 unleaded averages 156.7p — making diesel 31.4p per litre more expensive. However, diesel engines are typically 15–20% more fuel-efficient, which can offset the higher pump price for high-mileage drivers.
Is B7 diesel bad for my engine?
No. B7 diesel is designed for all diesel engines sold in the UK. All manufacturers approve its use. The 7% biodiesel component is well within the tolerance of modern diesel fuel systems.
What is the cheapest diesel in the UK today?
The cheapest B7 diesel right now is 123.9p per litre at MIDWAY SERVICE STATION, POST OFFICE, 351, SLIGO ROAD, LETTERBREEN, ENNISKILLEN, BT74 9FH, ENNISKILLEN. The UK average is 188.1p.
Should I use premium diesel instead of B7?
Premium diesel costs an average of 20.0p more per litre than standard B7. It contains cleaning additives that can benefit engines over time, but for most drivers the standard B7 grade is perfectly adequate.
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