How to calculate fuel consumption manually?

Fill up the tank and reset the trip meter. At the next fill-up, note how many gallons/liters were added and how many miles/km you drove. Divide the distance by the fuel amount. Example: 410 miles ÷ 38 gallons = 10.79 mpg.

How to calculate cost per mile driven?

To find out how much you spend per mile, divide the price of a gallon of fuel by your car's average consumption. Example: If gas costs $4.00 and the car gets 20 mpg, the cost is $0.20 per mile.

What causes a car to use more fuel?

Under-inflated tires, excessive air conditioning use, heavy vehicle load, and aggressive acceleration are the main factors that reduce range and increase fuel consumption.

Fuel Consumption Calculator

Discover your vehicle's fuel efficiency across four different measurement modes. Know exactly how much you achieve per gallon or liter.

Enter your recent refueling data and select your preferred unit

How does this tool work?

Enter distance traveled: In miles or kilometers.
Enter fuel used: In gallons or liters.
Click Calculate: The tool computes fuel efficiency (MPG or L/100km).
View result: See miles per gallon (US/UK) or liters per 100 km, depending on units selected.
Estimate costs: Optionally enter fuel price to compute cost per mile/km.

Fuel consumption calculators measure vehicle efficiency. The two common metrics are miles per gallon (MPG) and liters per 100 kilometers (L/100km). The choice depends on region. This tool supports both unit systems and can also compute trip cost based on fuel price.

How to calculate fuel consumption?

Calculating efficiency is essential for financial control. This tool measures in four modes to suit any region:

Km/L & MPG

Calculates how much distance you cover per unit of fuel. Higher is better.

L/100km

The European standard. Shows how many liters you need to drive 100km. Lower is better.

1. Fill Up: Fill the tank and reset the trip odometer.
2. Drive: Drive normally until the tank is low.
3. Refill: Fill up again and note the units added.
4. Math: For MPG/KML divide distance by fuel. For L/100km, divide fuel by distance and multiply by 100.

Example (Efficiency): 410 miles ÷ 38 gallons = 10.79 MPG

Ethanol vs. Gasoline Efficiency

Generally, ethanol yields about 30% less range than gasoline. If your car gets 30 MPG on gas, the expected average on ethanol is approximately 21 MPG.

Fuel Efficiency FAQ

The difference lies in the volume of the gallon. A US Gallon is approximately 3.785 liters, while a UK (Imperial) Gallon is about 4.546 liters. Because the UK gallon is larger, the MPG (UK) figure will always be higher for the same vehicle.

To convert L/100km to MPG (US), divide 235.21 by the L/100km value. For example, 10 L/100km is 23.52 MPG. Since L/100km measures fuel per distance and MPG measures distance per fuel, the relationship is inverse.

Yes. Rapid acceleration, high speeds, and frequent braking can decrease fuel efficiency by up to 30% on highways. Maintaining steady speeds and proper tire pressure are the most effective ways to optimize your vehicle's performance.

Onboard computers provide good estimates but can have a margin of error of 2% to 5%. The "Full Tank to Full Tank" manual method remains the gold standard for verifying real-world consumption.

L/100km is often preferred by engineers because it shows the direct cost of a trip. If you know you have 300km to drive, L/100km tells you exactly how much fuel you need to buy, making budgeting simpler than Km/L.

Fuel Consumption Calculator

How does this tool work?

How to calculate fuel consumption?

Km/L & MPG

L/100km

Ethanol vs. Gasoline Efficiency

Fuel Efficiency FAQ

What is the difference between MPG (US) and MPG (UK)?

How can I convert L/100km to MPG?

Does driving style affect consumption significantly?

Is the car's onboard computer accurate?

Why use L/100km instead of Km/L?

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