Petrol Cost Calculator UK
Calculate petrol and diesel costs per journey, per mile and per year using real UK pump prices. Includes MPG converter and annual fuel cost estimator.
Journey Fuel Cost Calculator
UK Fuel Price Comparison by Type
| Fuel Type | Avg Price (p/L) | Cost per Gallon | Duty (p/L) |
|---|---|---|---|
| Unleaded Petrol (E10) | 145.0p | £6.59 | 57.95p |
| Diesel (B7) | 150.0p | £6.82 | 57.95p |
| Premium Petrol (E5) | 165.0p | £7.50 | 57.95p |
| LPG (Autogas) | 72.0p | £3.27 | 28.35p |
Prices are UK national averages as of early 2026. Supermarket forecourts typically 3–5p/L cheaper. Motorway services typically 10–15p/L more expensive. Source: RAC Fuel Watch, AA Fuel Price Report.
Fuel Cost Comparison: Car Types per 10,000 Miles
| Car Type | Typical MPG | Litres Used | Annual Fuel Cost | Cost per Mile |
|---|---|---|---|---|
| 1.4L Petrol Hatchback | 40 MPG | 1,136L | £1,647 | 16.5p |
| 2.0L Diesel Saloon | 55 MPG | 826L | £1,239 | 12.4p |
| Full Hybrid (e.g. Prius) | 62 MPG | 733L | £1,063 | 10.6p |
| PHEV (plug-in hybrid) | 80 MPG* | 568L | £824 | 8.2p |
| Large 4x4 / SUV (petrol) | 25 MPG | 1,818L | £2,636 | 26.4p |
*PHEV figure assumes 30% of miles driven on electric power. Based on 10,000 annual miles at petrol £1.45/L, diesel £1.50/L.
UK Fuel Duty and Taxation Explained
Understanding what you pay at the pumps requires knowing how UK fuel taxation works. The headline pump price of around 145p per litre for petrol comprises several distinct components that are worth understanding if you want to appreciate why UK petrol costs what it does and how it compares internationally.
Fuel Duty: 57.95p per litre
Fuel duty is a flat excise duty charged per litre sold. Since March 2022, the government has frozen fuel duty at 57.95p per litre for both petrol and diesel following a 5p per litre cut announced in Spring Statement 2022. Before that cut, fuel duty had been frozen for over a decade at 57.95p per litre. In 2026, despite ongoing pressure on public finances, the freeze has been maintained, providing some relief to UK drivers. Fuel duty raises approximately £25 billion per year for HM Treasury, making it one of the UK government's most significant revenue streams. By comparison, the average EU fuel duty rate is around 50–55p per litre equivalent, meaning UK drivers pay among the higher duty rates in Europe.
VAT: 20% on the Full Pump Price
Value Added Tax is charged at the standard rate of 20% on the entire pump price including the duty element. This creates a "tax on a tax" effect. At 145p per litre, VAT adds approximately 24.2p per litre. Together, duty and VAT account for approximately 56% of the typical petrol pump price, meaning less than half of what you pay at the forecourt covers the actual cost of the crude oil, refining, transportation and retailer margin.
MPG Explained: UK vs US Gallons
Miles per gallon in the UK uses the Imperial gallon of 4.54609 litres, while the US gallon is only 3.785 litres. This means UK MPG figures are approximately 20% higher than the equivalent US MPG. A car achieving 50 UK MPG would be rated at about 42 US MPG. When researching imported vehicles or American car reviews, always check which gallon standard is being used. To convert UK MPG to litres per 100 kilometres (the European standard), use the formula: L/100km = 282.5 divided by MPG. So 50 MPG = 5.65 L/100km.
WLTP vs Real-World MPG
Since September 2017, new cars in the UK and EU have been tested using the Worldwide Harmonised Light Vehicle Test Procedure (WLTP), which replaced the older NEDC test. WLTP is more realistic than NEDC but still conducted in controlled laboratory conditions. Real-world driving typically achieves 10–20% less than the WLTP figure because the test does not account for traffic congestion, high motorway speeds above 130 km/h, use of air conditioning and heating, cold starts in winter, or carrying additional passengers and luggage. The Honest John Real MPG database, which collects real-world fuel consumption data from thousands of UK drivers, consistently shows average real-world figures around 15% below official WLTP claims.
Top 10 Eco-Driving Tips to Save Fuel
- Maintain correct tyre pressure — under-inflation by 8 PSI increases fuel use by around 3%
- Remove roof boxes and roof racks when not in use — they add 15–30% drag on motorways
- Accelerate smoothly and anticipate traffic to avoid harsh braking
- Use the highest practical gear — aim for 2,000–2,500 rpm in petrol, 1,500–2,000 in diesel
- Switch off the engine if stationary for more than 60 seconds (modern stop-start does this automatically)
- Remove unnecessary weight from the boot — 50kg extra weight increases fuel use by about 2%
- Use air conditioning sparingly in town — below 50 mph, open windows are more efficient
- Service your car regularly — dirty air filters, worn spark plugs and old engine oil all reduce economy
- Plan routes to avoid congestion and minimise cold starts — short journeys under 5 miles are particularly inefficient
- Use cruise control on motorways to maintain a steady speed and reduce fuel consumption by 5–10%
Frequently Asked Questions
What is the average petrol price in the UK in 2025?
As of early 2026, average UK petrol prices are approximately £1.45 per litre for unleaded petrol (E10) and £1.50 per litre for diesel. Prices vary by region and supermarket forecourt, with supermarkets typically 3–5p per litre cheaper than motorway services. The RAC and AA publish daily fuel price trackers to help drivers find the best local prices.
How do I calculate fuel cost per mile?
To calculate fuel cost per mile, first convert MPG to litres per mile by dividing 4.546 (litres per Imperial gallon) by your MPG figure. Then multiply by the fuel price per litre. Example: 40 MPG at £1.45/litre = (4.546 ÷ 40) × £1.45 = 16.5p per mile. Our calculator above does this automatically for you in both miles and kilometres.
How much fuel duty is included in UK petrol prices?
UK fuel duty is 57.95p per litre for both petrol and diesel. On top of this, VAT at 20% is charged on the full pump price including the duty, adding approximately 24p per litre at current prices. Together, duty and VAT account for over 55% of the typical pump price. Fuel duty alone raises approximately £25 billion per year for the Treasury and has been frozen since March 2022.
What is the difference between WLTP and real-world MPG?
WLTP is the official laboratory test for fuel economy. Real-world MPG is typically 10–20% lower because tests do not replicate UK traffic, heating and air conditioning use, motorway speeds, or cold weather. The Honest John Real MPG database shows average real-world figures are approximately 15% below WLTP claims. Always use real-world MPG figures for accurate journey cost planning.
Is it cheaper to drive a petrol, diesel or hybrid car per mile?
Per mile fuel costs for 10,000 annual miles: a 1.4L petrol at 40 MPG costs approximately £1,647/year; a 2.0L diesel at 55 MPG costs around £1,239/year; a full hybrid at 62 MPG costs about £1,063/year. However, diesel cars have higher purchase prices and servicing costs. Factor in total ownership costs, not just fuel, when choosing your next car.
How can I improve my car's fuel economy?
Key eco-driving techniques include: maintain correct tyre pressure (under-inflation reduces economy by up to 3%); remove roof racks when not in use; accelerate and brake smoothly; use the highest practical gear; switch off if stationary for more than 60 seconds; keep the boot free of unnecessary weight; service regularly including air filter and spark plug replacement.
What is the UK average car fuel economy?
The average new car sold in the UK achieves around 45–50 MPG on the WLTP test, equating to roughly 38–42 MPG in real-world driving. The average across all cars on UK roads is closer to 35–38 MPG. Small city cars typically achieve 45–55 MPG, family hatchbacks 35–50 MPG, and larger SUVs 25–40 MPG in real-world use, according to SMMT data.