Journey Planner
Fuel Cost
Calculator
UK Avg Petrol
~145p/litre
Avg Car MPG
45 MPG
Work out your journey fuel cost before you set off. Enter the distance in miles, your vehicle's fuel efficiency in MPG or litres per 100 km, and the current fuel price in pence per litre. The calculator instantly shows your total fuel cost, litres needed, cost per mile and return trip expense. Ideal for road trips, daily commutes and comparing running costs between vehicles across the United Kingdom.
Journey Details
Total Fuel Cost
£0.00
Litres Needed
0.0
Cost Per Mile
£0.00
Return Trip Cost
£0.00
How the fuel cost calculator works
Start by entering the one-way distance of your journey in miles. The UK uses miles for road distances, so you can read this straight off your satnav, Google Maps or a road atlas. The slider covers up to 1,000 miles, but you can type up to 5,000 for longer trips.
Next, set your vehicle's fuel efficiency. Choose between MPG (UK imperial miles per gallon) and litres per 100 km using the toggle buttons. Most UK drivers use MPG, which you can find on your V5C logbook, the manufacturer's spec sheet, or the DVLA combined figure. If you prefer the European standard of litres per 100 km, switch to that mode.
Then enter the current fuel price in pence per litre. Check your local forecourt, PetrolPrices.com or the RAC fuel watch for today's price. The slider covers 100p to 250p per litre.
The calculator converts your MPG to litres needed using the UK imperial gallon (4.546 litres), multiplies by the price per litre to get your total cost, and also shows cost per mile and a return trip estimate. Results update instantly as you change any input.
What you need to know about fuel costs in the UK
Fuel prices in the United Kingdom include both fuel duty and VAT. As of 2025/26, fuel duty is 52.95p per litre and VAT is charged at 20% on the total price including duty. This means roughly 55-60% of the pump price goes to the government in taxes.
Prices vary across the UK. Supermarket forecourts such as Asda, Tesco, Sainsbury's and Morrisons are typically the cheapest, often 5-10p per litre less than branded stations. Motorway service stations are consistently the most expensive, sometimes 15-25p per litre above the national average.
The average new petrol car in the UK achieves a combined figure of around 40-50 MPG (imperial). Diesel vehicles tend to be more efficient at 50-65 MPG, which partly offsets their higher per-litre fuel price. Hybrid vehicles can reach 60-80 MPG in mixed driving conditions.
Real-world fuel economy is typically 10-15% lower than the manufacturer's WLTP combined figure. Short journeys with cold starts, heavy traffic, air conditioning and roof boxes all reduce efficiency. Keeping tyres at the correct pressure, driving smoothly and removing unnecessary weight can help you get closer to the official rating.
HMRC allows employers to reimburse employees at the Advisory Fuel Rate (AFR) for business mileage in company cars. For private vehicles used for business, the Approved Mileage Allowance Payment (AMAP) rate is 45p per mile for the first 10,000 miles and 25p per mile thereafter.
Frequently asked questions
How do I calculate fuel cost for a journey in the UK?
Divide your journey distance in miles by your vehicle's MPG rating to get imperial gallons needed. Multiply by 4.546 to convert to litres, then multiply litres by the price per litre to get total fuel cost. Use the fuel cost calculator above to do this instantly.
What is the difference between UK imperial MPG and US MPG?
A UK imperial gallon is 4.546 litres, while a US gallon is only 3.785 litres. This means a car rated at 40 MPG in the UK would be rated at roughly 33 MPG in US terms. Always check whether your MPG figure is imperial (UK) or US when using a fuel cost calculator.
What is a good MPG for a car in the UK?
A combined MPG of 40-50 is typical for modern petrol cars in the UK. Diesel vehicles often achieve 50-65 MPG. Hybrids can reach 60-80 MPG in mixed driving. The DVLA and manufacturer combined figures give a useful benchmark, though real-world economy is usually 10-15% lower.
How much does it cost to drive 100 miles in the UK?
At 45 MPG and 145p per litre, driving 100 miles costs roughly £14.60 in fuel. Your actual cost depends on your vehicle's efficiency and local fuel prices. Enter your own figures into the calculator above for an accurate estimate.
What is the current average petrol price in the UK?
As of early 2026, the average UK unleaded petrol price is around 140-150p per litre and diesel is around 148-158p per litre. Prices vary by region, with motorway service stations typically 10-20p per litre more expensive than supermarket forecourts.
How do I convert litres per 100 km to MPG?
To convert litres per 100 km to UK imperial MPG, divide 282.481 by the l/100 km figure. For example, 6.0 l/100 km equals about 47 MPG. The calculator above supports both units so you can enter whichever your vehicle uses.