Gas Cost Calculator
Enter distance, fuel efficiency, and gas price to calculate trip costs. Add tolls and parking for per-person road trip expenses.
Units
Trip
Fuel cost:
$46.67
- Fuel used: L
- 13.33 L
- 100 km ÷ 15 km/L × 3.50
Results are estimates based on your input. Actual fuel costs may vary due to driving conditions, air conditioning use, and real-world fuel efficiency differences from manufacturer specs.
How to Use
In the Fuel Cost tab, enter your trip distance, fuel efficiency (in km/L or mpg), and current gas price, then select one-way or round trip. The fuel cost is calculated instantly as you type.
Switch to the Trip Total tab to calculate per-person road trip expenses. Your fuel cost from the first tab is automatically carried over. Enter any tolls and parking fees, then set the number of people to split costs. Remainders are always rounded up.
Common use cases include planning weekend road trips, calculating work commute fuel reimbursements, and comparing catalog fuel economy vs. real-world efficiency (typically 70-80% of rated mpg). Try entering your EPA-rated mpg and then the same value multiplied by 0.75 to see the real-world cost difference.
How the Calculation Works
The fuel cost formula is straightforward: Fuel Used (L) = Distance divided by Fuel Efficiency, then Fuel Cost = Fuel Used multiplied by Price per Liter. For round trips, the distance is doubled before calculating. Total trip cost is the sum of fuel cost, tolls, and parking. Per-person cost uses Math.ceil() to round up fractional amounts.
Insight A: International Fuel Economy Standards. Different countries measure fuel efficiency differently. Japan and the US use km/L or MPG (distance per unit of fuel - higher is better). Europe, Canada, and Australia use L/100km (fuel per distance - lower is better). The same car rated at 7.5 L/100km in Germany equals 13.3 km/L in Japan and 31.4 mpg in the US. Conversion formulas: L/100km = 100 divided by km/L; mpg (US) = 235.215 divided by L/100km. This calculator supports both km/L and mpg inputs for flexibility across regions.
Insight B: Comparing Gas vs. EV Running Costs. To estimate an EV running cost, use: Distance (km) times Energy Consumption (kWh/km) times Electricity Rate ($/kWh). For example, 100 km at 0.15 kWh/km with electricity at $0.15/kWh equals $2.25. By comparison, a gasoline car at 15 km/L with gas at $1.30/L costs approximately $8.67 for the same trip. EV cost calculation is outside the scope of this tool, but this comparison illustrates why real-world fuel efficiency matters. Note that actual gas mileage is typically 70-80% of manufacturer ratings due to driving conditions.
FAQ
- How much does real-world fuel economy differ from EPA/manufacturer ratings?
- Real-world fuel economy is typically 70-80% of the manufacturer rated figure. Key factors include air conditioning use, stop-and-go traffic, aggressive acceleration, and tire pressure. To estimate realistic costs, try entering both the rated mpg and 75% of that value, and compare the results.
- Does highway driving use more or less fuel than city driving?
- Highway driving at a steady speed is generally more fuel-efficient than city driving with frequent stops. However, tolls add to the overall cost. Use the Trip Total tab to enter toll fees and see which route is cheaper overall when comparing highway vs. surface roads.
- Can I use this to calculate work mileage reimbursements?
- Yes. Enter your commute or business trip distance, your vehicle fuel efficiency, and the current gas price to get an estimated fuel cost. Note that many companies use a fixed per-mile or per-km rate for reimbursements - check your company policy and use this tool result as a reference only.
- What is the difference between mpg (US) and mpg (Imperial/UK)?
- US gallons and Imperial (UK) gallons are different sizes. 1 US gallon = 3.785 L, while 1 Imperial gallon = 4.546 L. This calculator uses US gallons for mpg conversions (1 mpg US approximately equals 0.425 km/L). If you have UK mpg figures, multiply by 1.201 to convert to US mpg before entering, or simply use the km/L input instead.
- Does this work for hybrid or electric vehicles (EVs)?
- For hybrids, yes — just enter your real-world fuel efficiency (km/L or mpg) and the calculation works the same as any gasoline car. For EVs, this tool does not apply: EVs run on electricity, not gasoline, so you would calculate running costs using energy consumption (kWh/km) times your electricity rate instead. As a rough comparison, a 100 km trip in a typical EV (0.15 kWh/km at $0.15/kWh) costs about $2.25, while a gasoline car at 15 km/L with gas at $1.30/L costs around $8.67 for the same distance. EV cost calculation is outside the scope of this tool.