UK Petrol Cost Calculator
Work out how much a journey costs based on current petrol prices, your car's mpg, and your travel frequency.
How to use this petrol price UK calculator
This tool is designed for quick everyday budgeting. Enter the current petrol price at your local station in pence per litre, your distance in miles, and your car's fuel efficiency in UK mpg. You can also add how many similar trips you make each month to estimate monthly and annual fuel spend.
What you get instantly
- Fuel required for one trip (litres)
- Cost per mile
- Total cost per trip
- Monthly and yearly petrol estimate
How the calculation works
The calculator uses the standard UK conversion:
- 1 UK (imperial) gallon = 4.54609 litres
- Litres used = (Distance in miles / UK mpg) × 4.54609
- Trip cost = Litres used × (price in pence / 100)
Because fuel prices change often, the most accurate approach is to update the pence-per-litre value whenever you fill up.
Example: commuting in the UK
Suppose your local unleaded price is 145p per litre, your round trip is 25 miles, and your car does 42 mpg (UK). The calculator estimates your cost per trip, then scales it to monthly and annual totals. This makes it easy to compare transport choices, remote work days, or the value of a more efficient vehicle.
Ways to reduce petrol costs
- Maintain correct tyre pressure to reduce rolling resistance.
- Drive smoothly: avoid harsh acceleration and heavy braking.
- Remove unnecessary weight from the boot.
- Combine errands into one trip to reduce cold starts.
- Compare supermarket and independent station prices before filling up.
- Track mpg over time to spot maintenance issues early.
UK petrol calculator FAQ
Is this using UK mpg or US mpg?
It uses UK mpg. UK gallons are larger than US gallons, so make sure your car's figure matches UK mpg for accurate results.
Can I use this for motorway trips?
Yes. Just enter the expected trip mileage and your realistic mpg for motorway driving. If your mpg changes by route, run a second calculation and compare.
Does this include parking, tolls, or congestion charges?
No. This page calculates fuel cost only. For full trip budgeting, add parking fees, tolls, ULEZ/congestion charges, and wear-and-tear costs separately.