Remove unnecessary weight from boot and roof racks
Plan routes to avoid traffic congestion where possible
Service your car regularly (clean air filters improve MPG)
Consider trip-chaining rather than multiple short journeys
Fuel Cost Calculator UK 2025/26
Use our free Fuel Cost Calculator to estimate your car’s running costs. Whether you drive petrol, diesel, or hybrid, calculate your fuel bills, cost per mile, and see how much you could save by switching to an electric vehicle.
How Much Does Fuel Cost per Mile?
The cost per mile depends on three factors:
Fuel price per litre (currently averaging 145p-150p across the UK)
Your car’s fuel economy (MPG – miles per gallon)
Driving conditions (city driving reduces MPG by 15%, motorway can improve it by 5%)
Fuel Type
Typical MPG
Cost Per Mile (at 148p/L)
Small Petrol Car
45-50 MPG
~25-28p/mile
Family Petrol
35-40 MPG
~30-35p/mile
Diesel Car
45-55 MPG
~28-32p/mile
Hybrid
50-60 MPG
~22-26p/mile
Electric Vehicle
3.5 mi/kWh
~7p/mile (home charging)
Fuel Prices Across the UK (2025)
Fuel prices vary significantly depending on where you are in the UK:
Region
Petrol (p/litre)
Diesel (p/litre)
London
148-152p
149-153p
South East
147-150p
148-151p
Midlands
145-148p
146-149p
North West
144-147p
145-148p
Scotland
142-146p
143-147p
Tip: Use supermarket stations for cheaper fuel. Asda, Sainsbury’s, and Tesco often beat major brands by 2-4p per litre.
Understanding Your Car’s MPG
What is MPG?
MPG (Miles Per Gallon) tells you how many miles your car can travel on one gallon of fuel. The higher the MPG, the more efficient your car and the less you’ll spend on fuel.
Real-World vs Official MPG
Official WLTP MPG figures are usually optimistic. Expect to achieve 10-20% less in real-world driving, especially in stop-start city traffic.
Improving Your Fuel Economy
Maintain steady speeds using cruise control on motorways
Keep tyres correctly inflated (under-inflated tyres reduce MPG by 1-3%)
Remove roof racks and heavy items from the boot
Use air conditioning sparingly (increases fuel consumption by 5-10%)
Service your car regularly — a clean engine runs more efficiently
Petrol vs Diesel vs Hybrid: Which is Cheapest?
Factor
Petrol
Diesel
Hybrid
Fuel Cost
Medium
Slightly higher
Lowest per mile
Purchase Price
Cheapest
~£1,000-2,000 more
~£2,000-4,000 more
City Driving
Poor MPG
Very poor MPG
Excellent MPG
Motorway Driving
Good MPG
Best MPG
Good MPG
CO2 Emissions
Medium
Highest
Lowest
Verdict: If you mostly drive in town, a hybrid makes most financial sense. For high-mileage motorway drivers, diesel still offers the best balance. For mixed use with low annual mileage, petrol is often cheapest overall.
Switching to Electric: How Much Could You Save?
Electric vehicles cost significantly less to run than petrol or diesel cars:
Home charging: Around 7p per mile (at 24.5p/kWh electricity)
Public rapid charging: Around 12-15p per mile
Annual savings: For someone doing 10,000 miles/year, switching to EV saves £400-£800 per year on fuel
Our calculator shows your potential EV savings based on current fuel and electricity prices.
Frequently Asked Questions
How do I find out my car’s actual MPG?
Fill your tank completely, reset your trip meter, drive until you need to refuel again, then divide miles driven by gallons added. Repeat over several tanks for an accurate average.
Does driving faster increase fuel consumption?
Yes. Air resistance increases exponentially with speed. Driving at 70mph uses 20-30% more fuel than at 55mph. Maintaining 60-65mph on motorways maximises MPG.
Should I fill up when the moon is full?
No, that’s a myth. However, filling up early morning or late evening can help slightly — underground tanks are cooler and fuel is denser, giving you slightly more energy per litre.
What is the most economical speed for my car?
Most petrol cars achieve best MPG between 45-55 mph. Diesels peak at 50-60 mph. Hybrids excel below 35 mph where their electric motors do most of the work.
Does fuel quality affect running costs?
Premium fuels claim to improve MPG by 1-3% but cost 5-10p more per litre. For most modern cars, standard fuel is fine. Premium may pay off in high-performance or turbocharged engines.
How often should I fill up?
Fill up when your tank reaches quarter full to avoid running low. Don’t let it drop below 10% — sediment can clog fuel filters. Regular top-ups maintain consistent performance.
Is diesel really cheaper to run?
Only for high-mileage drivers. Diesel costs slightly more per litre but gives better MPG. For under 15,000 miles/year, petrol is often cheaper total. Above 20,000 miles/year, diesel wins.
