Gas Trip Cost Calculator
Calculate total gas cost for any road trip in seconds.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Gas Trip Cost Calculator
Planning a road trip or evaluating whether to drive vs. fly? This calculator gives you the total fuel cost for any drive in under 10 seconds. Here is how to get an accurate estimate.
- Enter your trip distance. Use Google Maps or your navigation app to get the exact mileage for your route. For a round trip, double the one-way distance.
- Enter your fuel economy. Use your vehicle's real-world MPG from your last fill-up, not the EPA estimate. You can find this in your car's trip computer or calculate it with the MPG Calculator.
- Enter the gas price. Use the current price at the stations along your route. GasBuddy or the AAA fuel gauge report show current average prices by state.
- Read your result. The calculator shows total fuel cost, gallons needed, and cost per mile. Use Share to send the estimate to a travel partner, or Copy to paste it into a trip budget spreadsheet.
About the Gas Trip Cost Calculator
The formula divides distance by MPG to get gallons needed, then multiplies by the fuel price. A 300-mile trip in a vehicle getting 28 MPG at $3.40 per gallon costs $36.43 in fuel. Gas is rarely the largest cost of a road trip (hotels, food, and time usually dwarf it), but it is the most predictable. This calculator helps you compare different route options, evaluate whether renting a more fuel-efficient car is worth it, or settle debates about who owes what on a shared trip.
Frequently Asked Questions
How accurate is this gas cost estimate?
The estimate is as accurate as your inputs. If you use your real-world MPG (not the EPA rating) and check current local gas prices, the result is typically within 5-10% of actual cost. Highway driving at steady speeds usually beats the EPA estimate; stop-and-go city driving often falls short. Use the MPG Calculator after your last fill-up to get your actual fuel economy.
Should I use city or highway MPG for a road trip?
For a mostly highway road trip, use your highway MPG. For a mix of city and highway, use the combined EPA estimate or your observed real-world MPG. Most vehicle specs list both city and highway figures; the combined rating is roughly 55% city and 45% highway weighting. For long interstate drives, many modern vehicles actually exceed their EPA highway rating at consistent 65-70 mph speeds.
Is it cheaper to drive or fly for a road trip?
For 1-2 people, flying is often cheaper for trips over 500 miles when you account for just the gas cost. For 3-4 people splitting costs, driving almost always wins up to 1,000+ miles. However, gas is only part of the drive cost: add tolls, parking, food, and lodging if overnight stops are needed. The Road Trip Cost Splitter helps you calculate the full picture and split it among passengers.
How do I find current gas prices along my route?
GasBuddy (gasbuddy.com) shows current prices at specific stations along any route. The AAA fuel gauge report provides daily state averages. Google Maps also shows gas station prices when you search for gas stations along your route. Prices can vary 20-40 cents per gallon within a few miles, so checking ahead and filling up in lower-priced areas can meaningfully reduce your total fuel cost on a long trip.