The basic formula is: trip miles ÷ miles per gallon × price per gallon. A 600-mile trip in a 30-MPG vehicle uses about 20 gallons. At $3.50 per gallon, that is about $70 in fuel.
Use realistic MPG
Your dashboard average or recent fuel-economy history may be more useful than a best-case highway rating if the trip includes city driving, mountains, traffic, or heavy loads.
Remember the entire route
Include the return trip, local driving at the destination, detours, and any planned side trips.
Other road-trip costs
Tolls, parking, food, lodging, and wear on the vehicle are separate from fuel. A gas estimate is only one part of a travel budget.
Use the calculator
Open the Fuel Cost Calculator and enter your own MPG and gas price.