Enter your one-way distance, fuel economy, and gas price to estimate fuel cost and gallons needed for a one-way or round trip.
Advanced options
Table of contents
How to use our Trip Fuel Cost Calculator
- Find the one-way driving distance in your map or navigation app and enter it in One-way driving distance.
- Choose One way or Round trip. Choose Round trip only if the distance you entered covers one direction.
- Enter your expected fuel economy and select the matching format shown by your dashboard, vehicle label, or manual.
- Enter the gas price you expect to pay and choose whether that price is per US gallon or per liter. Then select Calculate.
- Check Total trip distance used, Fuel economy used after conversion, and Gas price used after conversion before using the estimated fuel cost. Open Advanced options for a planning range or equal shares.
Definitions
US MPG: Miles driven per US gallon of fuel. A higher number means less fuel used for the same trip.
Kilometers per liter (km/L): Kilometers driven per liter of fuel. A higher number means less fuel used.
Liters per 100 km (L/100 km): Liters of fuel used to travel 100 kilometers. A lower number means less fuel used.
Expected gas price: The price you expect to pay for fuel, entered as dollars per US gallon or dollars per liter.
Fuel needed for the trip: Estimated fuel consumed over the trip, shown in US gallons. It does not predict fuel stops.
Fuel cost per mile: Estimated fuel spending for each mile using the base fuel economy and gas price.
Unit conversions: One US gallon equals 3.785411784 liters, and one mile equals 1.609344 kilometers. [1]
Common mistakes and quick fixes
Mistake: Entering the full there-and-back distance, then choosing Round trip.
Fix: Check One-way driving distance and then recalculate. Enter only the one-way distance and let Round trip double it.
Mistake: Using US MPG for a number shown as km/L or L/100 km.
Fix: Check One-way driving distance and then recalculate. Choose the fuel economy format printed next to your number before calculating.
Mistake: Entering a per-liter price while the price unit is set to $ per US gallon.
Fix: Check One-way driving distance and then recalculate. Match the gas price unit to the pump sign or price source.
Mistake: Using a best-ever highway MPG number for a trip with traffic, hills, passengers, or cargo.
Fix: Check One-way driving distance and then recalculate. Use MPG from similar driving, or enter possible MPG and price changes for a planning range.
Mistake: Entering only one of the two possible change percentages.
Fix: Check One-way driving distance and then recalculate. Enter both percentages to calculate a low and high estimate, or leave both blank for the base estimate.
Mistake: Treating the fuel estimate as the full cost of the trip.
Fix: Check One-way driving distance and then recalculate. Add tolls, parking, food, lodging, and other charges separately.
Limitations & Key Assumptions / Boundary Conditions
- The estimate includes fuel only. It excludes tolls, parking, maintenance, lodging, food, and other trip expenses.
- The entered fuel economy is treated as constant for the whole trip. Traffic, speed, weather, elevation, cargo, tire pressure, and driving style can change actual fuel use.
- The entered gas price is treated as the average price paid for all fuel used on the trip. Prices can vary by place and time.
- US MPG means miles per US gallon. UK MPG is not supported because an Imperial gallon is a different size.
- Fuel needed estimates consumption, not tank capacity, fuel already in the tank, refueling stops, or fuel-stop locations.
- Low and high estimates are planning scenarios based on your percentages. They are not guaranteed minimum or maximum costs.
- Equal fuel cost per person assumes each person pays the same amount.
Methodology
Calculation method
The calculator uses the entered one-way distance once for a one-way trip and twice for a round trip. It converts km/L or L/100 km to US MPG, and a per-liter price to dollars per US gallon, before calculating fuel use and cost. The mile, kilometer, liter, and US gallon conversions use exact defined relationships. [1]
Total trip distance = one-way driving distance x 1 or 2
Fuel needed (US gallons) = total trip distance / fuel economy used after conversion
Estimated trip fuel cost = fuel needed x gas price used after conversion
Fuel cost per mile = gas price used after conversion / fuel economy used after conversion
If both change percentages are entered, the low estimate uses better fuel economy and a lower gas price. The high estimate uses worse fuel economy and a higher gas price. If a whole number of people is entered, the base fuel cost is divided equally among them.
Worked example
For a one-way 100-mile trip at 25 US MPG and $4.00 per US gallon, fuel needed is 4 US gallons and estimated fuel cost is $16.00.
100 miles / 25 US MPG = 4 US gallons
4 US gallons x $4.00 per US gallon = $16.00