Fuel Efficiency Calculator
The fuel efficiency calculator converts distance and fuel used into vehicle mileage, then shows the result in km/L, L/100km, and mpg. It also estimates trip fuel cost from distance, mileage, and price per litre. Use it for cars, bikes, scooters, taxis, delivery vehicles, or road trips where fuel cost and real-world efficiency matter more than brochure claims.
How to Use
- Select Calculate Mileage when you know distance driven and fuel used.
- Enter the distance and choose kilometres or miles, then enter fuel and choose litres or US gallons.
- Click Calculate Mileage to see km/L, L/100km, and mpg.
- Select Estimate Trip Cost when you know the trip distance, vehicle mileage, and fuel price per litre.
- Click Estimate Trip Cost to see litres needed, total fuel cost in rupees, and cost per kilometre.
Fuel Efficiency Formula
L/100km = 100 / km_per_L
mpg = km_per_L x 2.35215
Trip litres = distance / km_per_L
Trip cost = litres_needed x price_per_litre
Fuel efficiency can be expressed in two opposite ways. In India, km/L is familiar because it tells you how many kilometres the vehicle travels on one litre of fuel. Higher km/L is better. In many international contexts, L/100km is used because it tells you how many litres are consumed to travel 100 kilometres. Lower L/100km is better. The same vehicle can be described by both numbers, so understanding the conversion helps compare Indian mileage figures with international specifications.
The calculator converts distance to kilometres and fuel to litres first. Mileage is distance_km divided by fuel_L. L/100km is 100 divided by km/L. US mpg is calculated as km/L multiplied by 2.35215. Trip cost is then straightforward: divide trip distance by km/L to get litres needed, multiply by fuel price, and divide by distance for cost per kilometre. Real-world cost also depends on traffic, air conditioning, tyre pressure, load, road grade, maintenance, and driving style.
Worked Example
A car travels 420 km and uses 28 litres of petrol. Mileage = 420 / 28 = 15 km/L. L/100km = 100 / 15 = 6.67 L/100km. US mpg = 15 x 2.35215 = 35.28 mpg. If petrol costs ₹100 per litre, each kilometre costs 100 / 15 = ₹6.67.
For a 300 km trip in the same car, fuel needed = 300 / 15 = 20 litres. Total cost = 20 x ₹100 = ₹2,000. If traffic reduces mileage to 12 km/L, the same trip needs 25 litres and costs ₹2,500. This is why real mileage is more useful for budgeting than a single brochure value.
Fuel Efficiency of Popular Indian Vehicles
| Vehicle | Claimed mileage | Fuel type |
|---|---|---|
| Maruti Alto K10 | 24.4 km/L | Petrol |
| Maruti Baleno | 22.9 km/L | Petrol |
| Hyundai i20 | 20.9 km/L | Petrol |
| Tata Nexon (petrol) | 17.4 km/L | Petrol |
| Maruti Dzire (CNG) | 31.1 km/kg | CNG |
| Honda City (diesel) | 24.1 km/L | Diesel |
| Mahindra Scorpio N | 15.2 km/L | Diesel |
| Toyota Innova | 15.1 km/L | Diesel |
Real Mileage vs Claimed Mileage
Claimed mileage figures are useful for comparison, but real-world mileage is usually lower. Standard tests are performed under controlled conditions with defined speeds, smooth acceleration, limited accessories, and a prepared vehicle. Actual driving includes stop-and-go traffic, rough roads, idling, air conditioning, passengers, luggage, tyre variation, and driver habits. A small petrol hatchback may come close to its rated mileage on a steady highway run, but the same car may return much less in dense city traffic. A diesel SUV may be efficient on highways yet consume heavily during short urban trips.
The most reliable way to measure your own mileage is the full-tank method. Fill the tank completely, reset the trip meter, drive normally, then refill to full at the same pump style if possible. Divide kilometres driven by litres filled. Repeat over several tanks to reduce noise from pump cut-off variation and unusual traffic. For bikes and scooters, the same method works. Keep a small log of fuel, odometer, route type, and tyre pressure; patterns will appear quickly and help identify maintenance issues or changes in driving cost.
FAQ
What is good mileage for a car in India?
Good mileage depends on vehicle type, fuel, transmission, route, and driving style. For small petrol hatchbacks, 16 to 22 km/L in mixed use is generally good. For compact SUVs, 12 to 18 km/L can be reasonable. Diesel cars often return higher highway mileage but may have higher purchase and maintenance considerations. CNG vehicles can be very economical, but fuel is usually measured in km/kg rather than km/L. The best comparison is against similar vehicles driven in similar traffic, not against a very different segment.
How do I calculate my bike's mileage?
Use the full-tank method. Fill the bike to a consistent level, reset the trip meter, ride normally, and refill to the same level. Note the kilometres travelled and the litres added. Mileage = kilometres travelled divided by litres filled. For example, if you ride 310 km and refill 6.2 litres, mileage is 310 / 6.2 = 50 km/L. Repeat the measurement over several refills because traffic, riding style, tyre pressure, and pump cut-off can change the result from one tank to another.
Why is ARAI mileage different from real mileage?
ARAI mileage is measured under standardized test conditions so vehicles can be compared consistently. Real roads are not standardized. City traffic, idling, aggressive acceleration, air conditioning, short trips, hills, tyre pressure, fuel quality, and passenger load all affect consumption. ARAI figures are therefore best treated as laboratory comparison numbers, not guaranteed daily mileage. Your own measured mileage is more useful for budgeting. If real mileage falls suddenly, check tyre pressure, air filter, wheel alignment, fuel quality, spark plugs, brakes, and driving pattern before assuming the vehicle is defective.
How can I improve fuel efficiency?
Drive smoothly, avoid harsh acceleration, maintain steady speeds, keep tyres inflated to the recommended pressure, remove unnecessary weight, use air conditioning sensibly, and service the vehicle on schedule. In manual vehicles, shift gears at appropriate engine speeds without lugging the engine. Avoid long idling and plan routes to reduce stop-start traffic where possible. Roof racks and open windows at highway speeds can increase drag. Good maintenance matters too: clogged filters, dragging brakes, poor alignment, and old spark plugs can all reduce mileage.
What is L/100km and how do I convert it to km/L?
L/100km means litres used to travel 100 kilometres. It is common in Europe and many international specifications. Lower values are better because they mean less fuel is consumed. To convert km/L to L/100km, divide 100 by km/L. For example, 20 km/L becomes 100 / 20 = 5 L/100km. To convert L/100km back to km/L, divide 100 by L/100km. For example, 6.67 L/100km becomes 100 / 6.67 = about 15 km/L.