UK road-trip estimate tool

Fuel Cost Calculator

Estimate a one-way or return trip using UK miles, imperial MPG and pence per litre. See the total cost, litres required, gallons used and the split cost per passenger.

Made for UK inputs Uses miles, imperial MPG and pence per litre instead of mixing UK and US fuel assumptions.
Useful for planning Quickly compare one-way and return journeys before setting off or splitting costs with friends.
Clear cost breakdown Shows litres, imperial gallons and per-person cost without making you do the conversion yourself.

Journey details

Return trip simply doubles the journey distance before estimating fuel use.
miles
UK mpg
p / litre
Enter the pump price in pence per litre, for example 145.9.
people
This page is a journey planning estimate. Real-world consumption may change because of traffic, speed, weather, route profile, tyre pressure and vehicle load.
Estimated journey cost
£0.00
One way
Breakdown Value
Journey distance used0.0 miles
Fuel required0.00 litres
Imperial gallons0.00 gal
Price per litre0.0 p
Cost per passenger£0.00
For UK calculations, 1 imperial gallon = 4.54609 litres. This page uses the UK gallon, not the smaller US gallon.

Related tools

Keep these journeys and household calculations together with the rest of your UK planning tools.

VAT Calculator Add or remove UK VAT and check the gross and net amount quickly. Working Days Calculator Count workdays and deadlines when planning travel for work or projects. Stones to Kg Converter Convert UK stones and pounds to kilograms when you need quick unit checks.

How this UK fuel calculator works

This page is designed around the way UK drivers usually think about fuel. Distances are entered in miles, vehicle efficiency is entered in imperial MPG, and the pump price is entered in pence per litre. The calculator converts those measurements into a single journey estimate without making you switch between systems manually.

The calculation behind the result

The estimate works in three steps. First, distance is divided by MPG to estimate the number of imperial gallons used. Second, imperial gallons are converted into litres using the UK conversion factor of 4.54609. Third, litres are multiplied by the pump price in pence and then converted into pounds.

Formula: total cost = ((distance ÷ MPG) × 4.54609 × price per litre in pence) ÷ 100

Why this is useful

  • It is useful for comparing one-way and return trips before you travel.
  • It helps with informal cost sharing when several people are splitting petrol or diesel.
  • It shows litres and gallons together, which makes the estimate easier to sense-check.

Frequently asked questions

Does this calculator use a UK gallon or a US gallon?

It uses the UK imperial gallon. That matters because a UK gallon is larger than a US gallon, so using the wrong conversion changes the estimated litres and total cost.

Is this suitable for exact reimbursement claims?

No. This page is a planning estimate. Employer mileage rates, business reimbursement rules and real-world fuel consumption may all differ from the simple journey estimate shown here.

Can I use it for petrol and diesel?

Yes. The calculator only needs your actual pump price and your vehicle efficiency. It does not assume a specific fuel type.