Road Trip Gas Calculator
Estimate a whole route’s fuel cost from total miles, average MPG and a price per US gallon.
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How to Use the Road Trip Gas Calculator
Add the mileage of every leg, including the return journey and planned detours. Enter that combined distance, the expected MPG and an average fuel price in US dollars per US gallon. Calculate to estimate the fuel budget for the whole route.
Formula and Explanation
Fuel cost = Total route miles ÷ MPG × Price
Total route miles divided by MPG gives the US gallons required. Multiplying that volume by the assumed price gives the fuel cost. The calculator treats all legs as one route with a single efficiency and price.
The distance is never automatically doubled. There are no individual stop controls, and tolls, parking, accommodation and meals are excluded. Changing prices or fuel efficiency along the route can make the actual cost different.
Worked Example
A route has legs of 180, 240 and 300 miles, totaling 720 miles. At 36 MPG, it needs 20 US gallons. At $3.75 per gallon, the estimated fuel cost is 20 × $3.75 = $75.00.
Frequently Asked Questions
Does the calculator add the return journey?
No. Enter the combined mileage of all legs you intend to drive, including the return. The tool uses your total exactly once.
How do I handle several stops?
Add the distance between each pair of consecutive stops before entering the total. This page accepts a combined distance rather than a separate input for each stop.
What fuel price should I use when prices vary?
Use a reasonable average price for your planning estimate. For more detail, calculate groups of legs separately using their expected prices and efficiencies, then add the costs.
Does the result include tolls and other travel costs?
No. This result covers fuel only. Budget tolls and other expenses separately, or use the Fuel Cost Calculator’s optional expense field.