FuelFoxWhat's actually in the price of UK petrol & diesel?
When you pay 145p per litre, more than half of it is tax. Here's the full breakdown of how that one figure is built up — duty, VAT, the wholesale cost of the fuel itself, and the (much smaller than you think) retailer margin.
On 15 April 2026 the UK average pump price was 145.0p per litre of petrol and 148.6p per litre of diesel. Before you put a single drop in the tank, you have already paid one fixed tax — Fuel Duty — and a variable one — VAT. Together those two are more than half the number on the sign.
The five layers behind every litre
Wholesale fuel arrives at the forecourt as a roughly known quantity: refining cost, transport, and the world price of crude oil. The retailer adds a margin, then HMRC and the Treasury take their share at the pump. Roughly:
What actually changes day-to-day
Duty and VAT don't move between Budget statements. The wholesale layer moves with crude — Brent prices propagate to UK forecourts on a roughly two-week lag. The retailer margin is the layer that varies betweenstations on a given day, and it's the only one you can do anything about as a driver.
The Competition & Markets Authority's 2023 road-fuels review found that the average supermarket margin on petrol had roughly doubled since 2019 — from about 4p to about 8p per litre. Not a conspiracy, but worth knowing: the chains nearest you may post very different prices on the same Tuesday morning.
Why prices vary by postcode
Duty and VAT are the same in Penzance and Inverness, but the pump price is rarely the same in both. Three things move it:
- Local competition. A supermarket forecourt across the road from another supermarket usually sets the floor for an entire town.
- Delivery cost. Highlands, islands and other remote forecourts pay more per litre to get the fuel there. Three- to five-pence regional differences are normal.
- Site economics. A motorway service area carries far higher rent and 24/7 staffing costs, so its margin is larger and the headline price reflects it.
What FuelFox can and can't do
We can show you the cheapest forecourt within sensible range of where you are right now. We can't change duty, VAT, or the Brent oil price. The thing under your control is which of the three or four nearby forecourts you actually pull into — and that's the layer the map is built around.
Where the numbers came from.
Every figure in this guide has a primary source — a UK government dataset, a regulator, or a long-running industry monitor. We don't cite blog posts.
Now do something with it.
You've read the theory. The map shows you the cheapest forecourt within sensible range right now. No signup.