Is higher or lower L/100km better?

Lower L/100km is better because it means your vehicle consumes fewer liters to travel 100 kilometers. In contrast, with MPG or km/L, higher numbers indicate superior efficiency.

How accurate is the vehicle dashboard fuel economy reading?

Vehicle dash computers estimate consumption based on electronic fuel injector pulse width and speed sensors. Studies demonstrate they are typically optimistic by 3% to 7%. The manual full-tank calculation method provides higher accuracy.

What is considered good fuel consumption today?

For conventional gasoline sedans, 6.0 to 7.5 L/100km (31 to 39 US MPG) is considered very good. Hybrids regularly achieve 4.0 to 5.0 L/100km (47 to 58 MPG), while large SUVs and trucks often consume 11.0 to 14.0 L/100km (17 to 21 MPG).

Calculation Methods5 min read

How to Calculate Fuel Consumption

Fuel consumption measures the volume of fuel a vehicle uses to travel a specific distance. In the metric system, it is commonly expressed in liters per 100 kilometers (L/100km) or kilometers per liter (km/L). In the United States, it is expressed as miles per gallon (MPG).

Open Fuel Consumption Calculator

Core Calculation Formula

Fuel Consumption (L/100km) = (Fuel Used in Liters ÷ Distance Traveled in km) × 100

Divide the liters consumed by the kilometers driven, then multiply by 100 to get L/100km.

Worked Example: 40 Liters used over 500 km = (40 ÷ 500) × 100 = 8.0 L/100km (or 12.5 km/L, 29.4 US MPG)

What Is Fuel Consumption?

Fuel consumption refers to the amount of fuel a vehicle consumes per unit of distance. Unlike fuel economy (which measures how far you travel per unit of fuel, such as MPG or km/L), fuel consumption is an inverse metric: lower numbers indicate greater efficiency.

Understanding your exact fuel consumption allows you to budget accurate trip costs, identify mechanical issues early (such as oxygen sensor or fuel injector deterioration), and optimize driving behavior.

How to Calculate L/100km (Liters per 100 Kilometers)

To calculate liters per 100 kilometers manually, record the total liters required to refill your tank and divide it by the number of kilometers traveled since the previous fill-up, then multiply by 100.

Step 1: Fill your fuel tank completely and reset your trip odometer to zero.

Step 2: Drive under typical daily conditions until you need to refuel.

Step 3: Return to the gas station, fill the tank to the first automatic shut-off click, and note the exact liters pumped.

Step 4: Divide the pumped liters by the odometer kilometers and multiply by 100.

Example: You drove 450 km and pumped 36 liters of fuel. (36 ÷ 450) × 100 = 8.0 L/100km.

How to Calculate km/L (Kilometers per Liter)

Kilometers per liter measures distance traveled per liter of fuel. This metric operates identically in concept to US MPG: a higher number represents superior efficiency.

Formula: km/L = Distance Traveled (km) ÷ Fuel Consumed (Liters).

Using the previous example: 450 km ÷ 36 liters = 12.5 km/L. To quickly convert between L/100km and km/L, simply divide 100 by the metric: 100 ÷ 8.0 = 12.5 km/L.

How to Calculate MPG (Miles per Gallon)

If you are measuring in miles and US gallons, divide the total miles driven by the gallons consumed.

Formula: US MPG = Miles Driven ÷ Gallons Used.

Example: Driving 320 miles on 10 US gallons equals exactly 32.0 US MPG. If you are in the United Kingdom or Commonwealth regions using Imperial gallons, note that 1 UK gallon equals 1.20095 US gallons, making UK MPG roughly 20% numerically higher for identical fuel efficiency.

How to Calculate Fuel Cost for a Journey

To determine the monetary cost of fuel for any journey:

Cost = (Total Distance ÷ MPG) × Price Per Gallon (in Imperial or US units)

Metric Cost = (Distance in km ÷ 100) × L/100km × Price Per Liter

Example: A 600-mile highway drive in a car averaging 30 MPG with gasoline at $3.50 per gallon requires 20 gallons (600 ÷ 30), totaling $70.00 ($0.117 per mile).