Road Trip Fuel Cost Estimate
Road Trip Fuel Cost Estimate
Estimating fuel cost before a road trip is a simple but genuinely useful calculation — comparing driving versus flying, budgeting for a trip, or deciding whether a more fuel-efficient rental car is worth the extra daily fee. It only takes three numbers: how far you are going, how efficiently the vehicle uses fuel, and the price of fuel along the way.The same arithmetic scales up to fleet and logistics planning, where fuel cost per mile is a major line item — a vehicle that is even a few miles-per-gallon less efficient adds up to real money over thousands of miles, which is exactly why fuel economy features so prominently in vehicle-buying decisions.
The fuel needed is gallons = distance/mpg, and the trip cost is cost = gallons × price per gallon. where D_trip is the trip distance in miles, FE_mpg is the vehicle's fuel economy in miles per gallon, price_gal is the price per gallon of fuel, and cost_trip is the resulting total fuel cost, all as plain numbers (miles, gallons, and dollars implied) since mixing mi/gal pint units here would auto-simplify to an awkward compound unit.
Inputs
D_trip := 350=350
FE_mpg := 28=28
price_gal := 3.85=3.85
Divide the trip distance by the fuel economy to find how many gallons of fuel the trip will burn.
gal_needed := D_trip/FE_mpg=12.5
Multiply the gallons needed by the price per gallon to get the total dollar cost of fuel for the trip.
cost_trip := gal_needed·price_gal=48.12
Results
A 350-mile trip in a 28 mpg vehicle burns about 12.5 gallons, costing roughly $48 at this fuel price — a quick number worth comparing against other travel options for the same distance. Fuel economy has an outsized effect on this cost: a less efficient vehicle at 20 mpg would burn noticeably more fuel for the identical trip, which is why fuel economy ratings matter more on longer trips than shorter errands.
Assumptions & limitations
- Constant average fuel economy for the whole trip (no city/highway mix breakdown).
- Constant fuel price for the whole trip.
- No tolls, parking, food, or other trip costs included.
- Distance, fuel economy, and price are plain numbers, not pint unit quantities, to keep the result cleanly in dollars.