Fuel Cost Calculator
Calculate how much fuel a trip will cost based on distance, your vehicle's fuel efficiency, and the price of fuel.
Improving fuel cost accuracy
Your vehicle's actual fuel efficiency varies with driving style, terrain, load, and conditions — highway driving typically achieves better mpg than city driving with frequent stops. For the most accurate estimate, use your vehicle's actual observed mpg from recent fill-ups rather than the manufacturer's rated figure.
For multi-leg trips with varying road types, calculating each leg separately with its expected mpg (city vs. highway) and summing the costs will produce a more accurate total than a single blended estimate.
A worked example
A 450-mile road trip in a car averaging 32 mpg, with gas at $3.60/gallon: gallons needed equals 450 divided by 32, approximately 14.06, and total cost is approximately 14.06 times $3.60, or about $50.63.
The same trip in a less efficient vehicle averaging 22 mpg would cost roughly $73.64 instead — over $23 more for the identical distance, purely from the difference in fuel efficiency.
Ways to reduce your fuel costs
Beyond choosing a more fuel-efficient vehicle, driving habits meaningfully affect real-world fuel economy — aggressive acceleration and braking, excessive idling, and higher highway speeds all reduce miles per gallon compared to steady, moderate driving.
Combining errands into fewer trips, maintaining proper tire pressure, and removing excess weight or roof cargo when not needed are all practical ways to improve fuel efficiency without changing vehicles.
Frequently asked questions
Does this account for highway vs city driving?
Use your vehicle's combined mpg rating for a realistic estimate, or adjust to city/highway mpg depending on your trip type.
How do I find my car's actual mpg?
Divide the miles driven since your last fill-up by the gallons used to fill the tank — tracking this over a few tanks gives a more reliable real-world average than the manufacturer's rated mpg.
Does this account for fuel price changes during a long trip?
No — this uses a single price estimate. For long trips, use an average expected price per gallon along your route for a more realistic total.
Does driving style really affect fuel economy that much?
Yes — aggressive acceleration and braking can reduce fuel economy by a meaningful margin compared to smooth, moderate driving, especially in stop-and-go conditions.