Road Trip Fuel Cost Calculator
Estimate road trip fuel cost and split it between travelers.
Estimate your trip fuel cost
Every money field below uses the same currency, whichever one you are working in. The results are shown in that same currency.
Trip estimate
Total trip cost
Enter your trip details to see an estimate.
- Total distance
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- Fuel required
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- Fuel cost
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- Added trip costs
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- Cost per traveler
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An estimate from the figures you entered. Real fuel use varies with traffic, terrain, weather, load, idling, and driving style.
Your entries and results stay in this browser. This tool does not send, save, or add them to the page address.
How to use this calculator
Pick the unit system you think in, enter the one-way distance, and say whether you are driving back. Add your vehicle’s fuel efficiency and the price you expect to pay, then the number of people sharing the cost.
Tolls, parking, and other costs are optional. Leave them at zero to see the fuel cost alone.
Methodology
Distance. The one-way distance is doubled when the round-trip option is selected. Optional costs are added once, not per leg, because tolls and parking are normally quoted for the whole trip.
Fuel. US units divide total distance by miles per gallon. Metric units multiply total distance by litres per 100 km and divide by 100. Both efficiency inputs are required to be greater than zero, which is what prevents a division by zero rather than any special case in the arithmetic.
Cost. Fuel cost is fuel required multiplied by the price per gallon or per litre. The total adds tolls, parking, and other costs, and the per-traveler figure divides that total by the number of travelers.
Currency. The calculator is deliberately currency-agnostic: it does no conversion and applies no currency symbol. Every monetary input and every monetary output is in the same single currency, whichever one you are using.
Units. Switching unit systems resets distance and fuel price to defaults for the new system and clears any previous result. This is intentional. A value entered as miles is not the same trip when read as kilometres, and a price per gallon is roughly four times a price per litre, so carrying numbers across the switch would quietly produce a wrong answer that still looks plausible.
Assumptions and limitations
The estimate assumes one constant fuel efficiency for the whole journey and one constant fuel price. Neither holds in practice.
Real consumption varies with traffic and stop-start driving, terrain and elevation change, weather and headwinds, how heavily the vehicle is loaded, tyre pressure, air conditioning and heating use, time spent idling, and driving style. Highway and city driving can differ substantially for the same vehicle. Fuel prices also vary between stations and along a route.
Distance and fuel figures are shown to one decimal place because the inputs are themselves estimates; more digits would suggest a precision the result does not have.
This tool estimates costs only. It is not a guarantee of what a trip will cost, and it makes no claim about saving money. Treat the output as a planning figure and leave room in your budget for the variation described above.
Frequently asked questions
How is the fuel requirement calculated?
In US units the total distance is divided by miles per gallon. In metric units the total distance is multiplied by litres per 100 km and divided by 100. Fuel cost is then the fuel required multiplied by the price you entered.
What does the round-trip option do?
It doubles the one-way distance before any fuel calculation. Tolls, parking, and other costs are not doubled, because those figures are usually quoted for the whole trip rather than per leg. Enter them as the total you expect to pay.
Which currency does the calculator use?
It is currency-agnostic. Fuel price, tolls, parking, other costs, and every monetary result all use whichever single currency you are working in. The calculator never converts between currencies.
What happens when I switch between US and metric units?
Distance and fuel price are reset to sensible defaults for the newly selected system, and any previous result is cleared. A distance in miles is not a distance in kilometres and a price per gallon is not a price per litre, so the calculator does not silently reinterpret the numbers you had entered.
Why does my real fuel use differ from this estimate?
A single efficiency figure cannot capture real driving. Traffic, terrain and elevation, weather and wind, vehicle load, tyre pressure, air conditioning, idling, and driving style all move actual consumption, often substantially.