How does driving type affect fuel consumption?

Urban driving with frequent stopping and starting typically uses 20% more fuel than your average MPG. Motorway driving at higher speeds uses about 10% more due to increased aerodynamic drag. Mixed driving is closest to your standard MPG figure.

Should I carry extra fuel for safety?

It is good practice to plan with a 10-15% fuel buffer. Never let your tank drop below a quarter, as running very low can draw sediment into the fuel system and stress the fuel pump. On long journeys, plan fuel stops every 200-250 miles.

Does the fuel type affect consumption?

Premium fuels (e.g. Shell V-Power, BP Ultimate) can marginally improve economy in some engines, typically by 1-3%. The price premium is usually around 10p per litre, so the maths rarely works out in favour of premium fuel for economy.

Should I fill up before or during a long journey?

Fill up before leaving, as motorway service station fuel is typically 15-20p per litre more expensive than supermarkets. If you need to refuel during the journey, leave the motorway at a junction and find a nearby supermarket station instead of using the services.

How do I estimate fuel for a journey I have not done before?

Use your known MPG figure (from brim-to-brim testing) with the journey distance from a route planner. Add 10-15% for motorway driving or 20% for hilly or stop-start urban routes. Always carry slightly more fuel budget than your minimum estimate.

CarCalcs

Journey Fuel Calculator

Calculate how much fuel you need for a specific journey, adjusted for driving type.

Journey Distance

Your MPG (UK)

Driving Type

Fuel Price (optional)

Leave blank to see fuel quantity only

How We Calculate This

This calculator adjusts your baseline MPG based on the type of driving, then works out the fuel requirement.

The Adjustment Factors

Mixed driving — uses your stated MPG as-is
Mostly motorway — reduces MPG by 10% (higher speed = more drag)
Mostly urban — reduces MPG by 20% (stop-start driving)

The Calculation

Adjusted MPG = Your MPG x adjustment factor
Gallons needed = Distance / Adjusted MPG
Litres needed = Gallons x 4.54609

Frequently Asked Questions

Related Calculators

MPG Calculator

Calculate your car's miles per gallon from distance and fuel used.

Fuel Cost Calculator

Work out the fuel cost for any journey based on distance and fuel price.

Litres Per 100km Calculator

Convert your fuel consumption to the European litres per 100km standard.

Fuel Tank Range Calculator

Find out how far you can drive on a full tank of fuel.

Annual Fuel Cost Calculator

Estimate your total yearly fuel spending based on mileage and consumption.

Last updated: February 2026

All calculations are estimates. Actual figures may vary based on driving conditions, vehicle specifications, and other factors.