Calculate Your Fuel Economy
Enter your trip distance and fuel used to estimate MPG, km/L, and L/100km. You can also add fuel price to estimate trip cost.
Why a Gas Mileage Calculator Matters
Fuel is one of the largest ongoing costs of owning a vehicle. A simple gas mileage calculator helps you understand how efficiently your car is performing and how much each trip really costs. Once you know your real-world mileage, you can make smarter decisions about route planning, driving habits, maintenance, and even when it might be worth upgrading to a more efficient car.
Manufacturer MPG ratings are useful, but they are estimates gathered under controlled conditions. Your daily commute, local traffic, weather, tire pressure, and load in the trunk can all change your true fuel economy. Tracking your own numbers gives you a more accurate baseline.
How This Calculator Works
The calculator uses your distance traveled and total fuel consumed over that same distance. From those two values, it calculates:
- US MPG (miles per gallon): Distance in miles ÷ fuel in US gallons.
- Imperial MPG: Distance in miles ÷ fuel in imperial gallons.
- km/L (kilometers per liter): Distance in kilometers ÷ fuel in liters.
- L/100km: Fuel in liters ÷ distance in kilometers × 100.
If you include fuel price, it also estimates total fuel cost and cost per mile/kilometer for that trip.
Quick Example
Scenario
You drove 280 miles and used 9.8 gallons. Enter those values and click calculate.
Result
Your gas mileage would be about 28.57 MPG (US). This can help you compare your current performance against previous fill-ups and identify trends.
Ways to Improve Fuel Economy
- Keep tires inflated to the recommended pressure.
- Avoid aggressive acceleration and hard braking.
- Remove unnecessary cargo weight.
- Combine errands to reduce cold starts.
- Stay current on oil changes and air filter replacement.
- Use cruise control on highways when safe.
- Plan routes to avoid stop-and-go congestion.
How Often Should You Track Mileage?
A practical approach is to log mileage at every fill-up. Over time, this creates a personal fuel economy history. If your MPG drops unexpectedly, it can signal issues such as underinflated tires, dragging brakes, poor alignment, worn spark plugs, or fuel system problems.
Seasonal changes are normal too. Many drivers see lower MPG in winter due to colder air, winter fuel blends, and increased engine warm-up time.
Frequently Asked Questions
Is higher MPG always better?
Yes. Higher MPG means you travel farther on the same amount of fuel, which usually means lower fuel cost and reduced emissions.
What is a good MPG?
It depends on vehicle type. Compact hybrids can exceed 45 MPG, while larger SUVs and trucks may be much lower. The key is to compare your car against its own expected range and watch for changes over time.
Can short trips hurt gas mileage?
Absolutely. Engines are less efficient before they fully warm up. Frequent short trips can noticeably reduce fuel economy.