Calculate your vehicle's fuel economy in MPG, cost per mile, and trip fuel costs with comparison charts and efficiency tips.
The Fuel Mileage Calculator helps you determine your vehicle's fuel economy, cost per mile, and total fuel expenses for any trip. Simply enter your distance traveled and fuel used to get an instant MPG reading, or plan a trip by entering distance and your vehicle's estimated MPG.
Fuel costs are often the second-largest vehicle expense after depreciation. Understanding your actual fuel economy helps you budget for trips, compare vehicles, identify when your car needs maintenance, and make smarter driving decisions. A drop in fuel economy often signals issues like underinflated tires, dirty air filters, or engine problems.
This calculator works in both US (MPG) and metric (L/100km) formats and provides comprehensive comparisons against EPA ratings, vehicle class averages, and historical fuel prices. Whether you're tracking daily commute costs, planning a road trip, or evaluating whether a hybrid would save you money, this tool delivers actionable insights. Check the example with realistic values before reporting.
Understanding your fuel economy saves money, helps maintain your vehicle, and enables smarter trip planning. This calculator turns raw numbers into actionable cost and efficiency insights. Keep these notes focused on your operational context. Tie the context to the calculator’s intended domain. Use this clarification to avoid ambiguous interpretation. Align this note with review checkpoints.
MPG = Distance (miles) / Fuel (gallons). Cost Per Mile = Fuel Price / MPG. Trip Cost = (Trip Distance / MPG) × Price Per Gallon. L/100km = (Liters / km) × 100.
Result: 28.0 MPG, $0.125/mile
350 miles ÷ 12.5 gallons = 28.0 MPG. At $3.50/gallon, that's $0.125 per mile or $43.75 for the full tank.
MPG (Miles Per Gallon) is the standard US fuel economy measure. Higher is better. L/100km (Liters per 100 Kilometers) is the metric equivalent — lower is better. The relationship is inverse: 30 MPG ≈ 7.84 L/100km. Some countries also use km/L, where higher is better like MPG.
Vehicle design (weight, aerodynamics, engine type) determines base efficiency. Driving behavior adds 20-30% variation: aggressive driving, speeding, excessive idling, and short trips all reduce MPG. Environmental factors include temperature (cold starts use more fuel), altitude, and wind. Maintenance factors include tire pressure, oil viscosity, air filter condition, and engine tune.
The biggest savings come from driving behavior, not fuel shopping. Maintaining 60 mph instead of 75 mph saves roughly 15% on fuel. Combining short trips saves cold-start fuel waste. Properly inflating tires saves 3-5%. Using the recommended oil grade saves 1-2%. Over 15,000 miles per year at $3.50/gallon, improving from 25 to 30 MPG saves $350 annually.
Fill your tank completely, reset your trip odometer, drive normally, then fill up again. Divide the miles driven by gallons to fill. Repeat for 3+ tanks for accuracy.
The US fleet average is about 25 MPG. Compact cars get 30-40 MPG, hybrids 40-60 MPG, and trucks/SUVs 18-25 MPG. Check EPA ratings for your specific model.
L/100km = 235.215 / MPG. For example, 30 MPG ≈ 7.84 L/100km.
EPA tests are lab-based. Real-world conditions like highway speed, AC use, idling, cold weather, and driving style typically reduce MPG by 10-20%.
Yes, significantly. Most vehicles are most efficient at 45-65 mph. Above 65, fuel economy drops roughly 7% for each 5 mph increase.
Running AC typically reduces fuel economy by 5-15% in city driving. At highway speeds, AC is more efficient than opening windows (which creates drag).