Fuel Cost per Trip Calculator

Fuel cost per trip calculator for road trip planning and budgeting

This fuel cost per trip calculator estimates how much fuel your vehicle will use for a specific journey and what that fuel will cost. It is designed for normal trip planning: commuting, weekend drives, longer road trips, and quick comparisons between routes or vehicles. You can work in either metric units (kilometres, litres per 100 km, price per litre) or imperial units (miles, MPG, price per gallon).

To use it, choose the unit system that matches the numbers you already have. Then enter the trip distance, your vehicle’s fuel efficiency, and the current fuel price. If you are planning a return journey, switch to round trip so the calculator automatically doubles the distance. If you are splitting fuel money with other people, enter the number of passengers to see the cost per person.

The results are broken into the numbers most people actually need: total fuel used, total trip fuel cost, and a simple cost-per-distance figure. Fuel used helps you check whether you will need a refuel stop, especially on longer drives. Total cost is the direct budget line item for the trip. Cost per kilometre or cost per mile is useful for comparing two routes with different distances, or comparing two vehicles with different fuel efficiency.

Assumptions and how to use this calculator

• Fuel efficiency is assumed to stay constant for the trip. Real-world consumption changes with speed, traffic, hills, load, tyre pressure, and wind.
• Fuel price is treated as a single price for the entire trip. If you cross regions with different prices, use an average price you expect to pay.
• Round trip doubles the distance. If your return route is different, use the one-way setting and enter the total distance instead.
• Passenger splitting is a simple division of the total fuel cost by the passenger count you enter.
• This calculator estimates fuel cost only. It does not include tolls, parking, maintenance, depreciation, or time costs.

Common questions

What if my car uses “km per litre” instead of “L/100km”?

This calculator uses L/100km in metric mode because it is common on vehicle spec sheets and makes trip fuel math straightforward. If you have km per litre (km/L), convert it by dividing 100 by km/L to get L/100km. Example: 14 km/L becomes about 7.14 L/100km (100 ÷ 14).

Why does the estimate not match what I actually spend?

Small differences are normal. Real fuel consumption varies with driving conditions. Heavy traffic, short stop-start routes, high speeds, strong headwinds, steep climbs, or a loaded vehicle can increase fuel use significantly. If you want a more realistic estimate, use a slightly worse efficiency number than your “best case” figure.

Should I use my dashboard average MPG or the manufacturer rating?

Your dashboard average is usually the better input because it reflects your driving style and typical conditions. Manufacturer ratings can be optimistic compared to real-world use. For trip planning, use your recent average from similar driving (highway vs city) if you can.

Does “round trip” always mean double the cost?

Only if the return distance and conditions are similar. If the return route is longer, shorter, or much slower, the real cost can differ. In that case, keep one-way selected and enter the total distance you expect to drive in one combined figure.

How do I estimate fuel cost per person for a group trip?

Enter the number of passengers you want to split the fuel cost across. The calculator will show a simple equal split. If you want a different split (for example, the driver pays less), use the total cost and do your own split rules afterwards.