CalcConsumo Combustible
Last updated: 2026-05-07
Enter your email and download a PDF report with your results.
| Liters (L) | Km (km) | |
|---|---|---|
| City | 25 L | 250 km |
| Suburban | 38 L | 375 km |
| Highway | 50 L | 500 km |
| Long haul | 75 L | 750 km |
| International | 100 L | 1000 km |
Fuel Economy Calculator: Optimize Your Vehicle’s Gas Mileage
The fuel economy calculator converts between MPG and L/100km and computes your vehicle's actual fuel consumption from distance traveled and fuel used. Whether you are tracking your weekly commute, budgeting for a road trip, or comparing vehicles before a purchase, understanding your real-world fuel economy helps you save money and reduce your environmental footprint.
You may also find the Depth of Field Calculator, Hyperfocal Distance Calculator, and Decibel Addition Calculator useful.
Fuel Economy Formulas
MPG = Miles / Gallons
L/100km = (Litres / Kilometers) × 100
L/100km = 235.215 / MPG
MPG (miles per gallon) expresses how far a vehicle can travel on a single gallon of fuel — a higher number means better efficiency. L/100km (liters per 100 kilometers) expresses how much fuel is consumed over a fixed distance — a lower number means better efficiency. The conversion factor 235.215 comes from the relationship between imperial/US gallons and kilometers: 1 US gallon = 3.78541 liters, 1 mile = 1.60934 km, and (100 × 3.78541) / 1.60934 ≈ 235.215.
To get your actual fuel economy, fill your tank completely, reset the trip odometer, drive normally until you refuel, then note the miles driven and gallons pumped. Dividing distance by fuel used gives you your real-world MPG, which is often different from the EPA or manufacturer estimates due to driving conditions, habits, and vehicle maintenance.
Worked Examples
Example 1: Highway Road Trip
You drive 385 miles on a full tank and refuel with 11.2 gallons. What is your fuel economy?
Calculation (MPG): MPG = 385 / 11.2 = 34.4 MPG
Conversion to L/100km: L/100km = 235.215 / 34.4 = 6.84 L/100km
This result indicates excellent highway fuel economy typical of a modern midsize sedan or compact car. At current fuel prices of $3.50 per gallon, this trip cost approximately $39.20 in fuel, or about 10.2 cents per mile.
Example 2: Mixed City and Highway Driving
Over a week of commuting and errands, you drive 298 miles and use 13.6 gallons of fuel.
Calculation (MPG): MPG = 298 / 13.6 = 21.9 MPG
Conversion to L/100km: L/100km = 235.215 / 21.9 = 10.74 L/100km
This mixed-driving result is typical for a midsize SUV or pickup truck. With fuel at $3.80 per gallon, your weekly fuel cost is $51.68. Tracking this over several weeks helps you identify whether seasonal changes, different driving routes, or vehicle maintenance issues are affecting your fuel economy.
Common Uses
- Tracking personal vehicle fuel efficiency over time to identify maintenance needs or driving habit changes
- Budgeting for long road trips by estimating total fuel cost based on distance and expected fuel economy
- Comparing fuel costs between different vehicles when considering a purchase or lease decision
- Verifying manufacturer EPA fuel economy ratings against real-world driving conditions and terrain
- Evaluating the financial benefit of switching to a hybrid, electric, or more fuel-efficient vehicle
- Calculating fleet fuel costs for small businesses, delivery services, or ride-sharing drivers to optimize operational expenses
Common Mistakes
- Using partial fill-ups instead of full-tank to full-tank measurements — partial fills introduce significant error because you cannot accurately measure fuel consumed
- Confusing US gallons with imperial (UK) gallons — an imperial gallon is 1.2 US gallons, which changes the MPG calculation by 20%
- Forgetting to reset the trip odometer at each fill-up, leading to accumulated mileage that does not reflect the fuel consumed
- Relying on the car's onboard computer display instead of manual calculation — in-dash economy displays can be optimistic by 5–10%
- Comparing MPG and L/100km directly without conversion — remember that higher MPG is better but higher L/100km is worse
Pro Tip
Track your fuel economy over at least five consecutive fill-ups to get a reliable average. A single tank can be skewed by a long idling period, short trips, or even a different gas station's pump calibration. Use a fuel tracking app or a simple spreadsheet to log date, odometer reading, gallons pumped, and cost. Over time, you will notice patterns: fuel economy typically drops 10–15% in winter due to cold engine operation, winter fuel blends, and increased rolling resistance from lower tire pressure. A sudden drop of more than 20% that persists for two or more tanks may indicate a mechanical issue such as a failing oxygen sensor, dirty air filter, or underinflated tires.
Frequently Asked Questions
MPG (miles per gallon) measures how many miles a vehicle can travel on one gallon of fuel — higher is better. L/100km (liters per 100 kilometers) measures how many liters of fuel are needed to travel 100 kilometers — lower is better. MPG is primarily used in the United States and United Kingdom, while L/100km is the standard in Europe, Canada, Australia, and most other countries.
For modern cars, good fuel economy is generally under 8 L/100km (over 30 MPG). Compact cars often achieve 5–7 L/100km (34–47 MPG) on the highway. SUVs and trucks typically get 10–15 L/100km (16–24 MPG). Hybrid vehicles can achieve 3–5 L/100km (47–78 MPG), and electric vehicles have an MPGe rating typically between 100–140 MPGe.
Key ways to improve fuel economy include maintaining proper tire pressure, removing excess weight from the vehicle, avoiding aggressive acceleration and hard braking, reducing highway speed (each 5 mph over 50 mph reduces fuel economy by about 7%), using cruise control on highways, keeping the engine properly tuned, and using the recommended grade of motor oil.
City driving typically gives lower fuel economy because of frequent stops, idling at traffic lights, and constant acceleration from a standstill. Highway driving is more efficient because the engine runs at a steady RPM with less braking and acceleration. However, very high highway speeds (above 60 mph or 100 km/h) increase aerodynamic drag and reduce fuel economy, creating a bell-shaped efficiency curve.