Petrol & Mileage Calculator
Use this simple tool to estimate fuel needed, trip cost, and real-world mileage after a refill.
1) Trip Fuel Cost Calculator
2) Mileage Calculator (Tank-to-Tank)
Enter your odometer readings and fuel filled to calculate actual mileage.
Why a petrol and mileage calculator matters
Fuel is one of the most regular and unavoidable expenses for daily commuters, road trippers, and delivery drivers. A petrol and mileage calculator helps you answer practical questions quickly: How much fuel will this trip need? What will it cost? Is my car becoming less efficient over time?
By checking these numbers regularly, you can improve route planning, compare vehicles more realistically, and reduce unnecessary driving costs.
What this calculator helps you do
- Estimate total trip fuel cost before you leave.
- Convert across common fuel-economy formats like km/L, L/100km, and MPG.
- Track real-world mileage using odometer and refill data.
- Measure cost per km for personal budgeting or business travel.
How the formulas work
Trip cost formula
The calculator first converts your efficiency into a common unit (km/L), then computes fuel usage:
- Fuel needed (L) = Distance (km) ÷ Efficiency (km/L)
- Total cost = Fuel needed × Petrol price per liter
- Cost per km = Total cost ÷ Distance
Mileage formula (tank-to-tank method)
This method uses real driving data and is generally more accurate than dashboard estimates:
- Distance traveled = End odometer − Start odometer
- Mileage (km/L) = Distance (km) ÷ Fuel added (L)
- Fuel consumption (L/100km) = 100 ÷ Mileage (km/L)
Quick example
Suppose your one-way trip is 85 km, your car returns 17 km/L, and petrol costs ₹102/L. If you also return the same day:
- Round-trip distance = 170 km
- Fuel needed = 170 ÷ 17 = 10 L
- Total cost = 10 × 102 = ₹1,020
This gives you a clear number to budget before you start the engine.
Tips to improve mileage and reduce petrol costs
Driving habits
- Avoid harsh acceleration and sudden braking.
- Maintain a steady speed on highways.
- Reduce long idling when parked.
Vehicle maintenance
- Keep tires inflated to recommended pressure.
- Replace air filters on schedule.
- Use the engine oil grade recommended by your manufacturer.
Planning and load management
- Combine errands into one route.
- Avoid carrying unnecessary weight.
- Use traffic-aware navigation to reduce stop-and-go driving.
Frequently asked questions
Is km/L better than L/100km?
Both are valid. km/L tells you how far you can go on one liter; L/100km tells you how much fuel you consume over a fixed distance. Choose whichever format is easier for you to compare.
How often should I calculate mileage?
At least once every 2–3 refuels. Tracking over multiple tanks smooths out temporary variations like traffic, weather, and load changes.
Why is actual mileage different from manufacturer claims?
Official figures are measured in controlled test conditions. Real roads include traffic, road slope, AC usage, payload, and driving style, all of which affect mileage.
Final thought
A few numbers can change your monthly fuel budget significantly. Use this calculator before trips and after refills to make smarter driving and spending decisions.