# 4 ways to calculate your car's fuel efficiency (MPG or KML)

As the price of gasoline is increasing, fuel efficiency is becoming an increasingly important factor. Knowing your car's kilometers per liter (KPL) (or miles per gallon) can help you determine if your car is sucking gas and therefore wasting money. Once you determine the KPL for your car, you can do many useful things, such as calculating how much an increase in the price of gasoline would affect your budget, and how a car with a better KPL would lower your monthly cost, or if your car has a lower KPL value than it should be because you need to go to the mechanic. Next, we will explain how to calculate it.

## Steps

### Method 1 of 4: Calculate Your Car's Fuel Efficiency

#### Step 1. Go to the gas station and fill the tank

This may hurt a bit, but it is the key to getting a true look at your car.

#### Step 2. Record the mileage

Before you even remove the gas manager, write down your current mileage. We will call this the Mileage A.

#### Step 3. Drive normally

To get as accurate a reading as possible, drive until the tank is less than half full. The further you can go before refueling, the better.

#### Step 4. Fill the tank again

Try to go to the same gas station and use the same dispenser as the first time, since it may be calibrated differently than another. This time, pay attention to how many liters it takes to fill the tank. Usually this is shown by the dispatcher. We will call this value Liters.

#### Step 6. Do the math

The formula to determine your KPL is this:

• KPL = (Mileage B - Mileage A) ÷ liters
• Subtract mileage A from mileage B. This will give you the number of miles you have driven since the last time you got gas.
• Divide your answer by the number of liters it took you to fill the tank again. This will give you the KPL value of your car.

### Method 2 of 4: Example

Let's say you have a new car and you want to record its mileage.

• Trip A: You put 8, 663 liters with 3,117 km
• Trip B: You put 9, 251 liters with 3579 km
• Trip C: You put 8, 876 liters with 4017 km

### Method 3 of 4: Calculate Mileage

• Trip A: The starting point does not count.
• Trip B: (3579 km - 3117 km) / 9.251 liters = 49.9 kpl
• Trip C: (4017 km - 3579 km) / 8,876 liters = 49,3 kpl

### Method 4 of 4: Additional Accuracy

#### Step 1. Check your mileage meter

Not all cars reflect an accurate measurement. This will not only reflect an incorrect number of kilometers that you have driven, but it will also give you an incorrect result of your KPL.

### Many roads have "mileage review sections." They are narrow roads of many kilometers that have the route that you have marked on the ground. If you are near one, use it. Otherwise, you can look on a map for a straight and narrow path or highway and mark a route that will ensure you about 5 or 10 km to verify

#### Step 2. Go to the first mark

Set your odometer (mileage meter) to 0 while passing the mark.

• At the end of the ride, write down the odometer result. An accurate odometer will tell you how far you have actually traveled.
• If the value it gives you is greater than the distance you have traveled, your gas efficiency is worse than what you have calculated. You really have traveled less distance than your odometer shows. Similarly, if your odometer is less than the distance you actually traveled, your KPL is greater than what you had calculated.

#### Step 3. Find the variance

We will call the variance the distance you actually traveled as "A" and the kilometers marked by the odometer as "T". We will call the variation "O". The formula to determine the variation is:

• O = A ÷ T.
• For example, if you traveled 5 km and your odometer says you traveled 4.5, your formula would be:
• O = 5 ÷ 4.5; O = 1,111. To get your actual mileage for the KPL formula, you must subtract mileage A from mileage B, as you normally would, and then multiply the result by 1,11 before dividing to calculate your KPL..
• If mileage B - Mileage A = 100, multiply by O (1, 11). In this example, you actually traveled 111 km.
• If your odometer says that you traveled 5.5 km, the formula would be:
• O = 5 ÷ 5.5; O = 0.91. Again, you must multiply mileage B- Mileage A by the value of O.
• If Mileage B-Mileage A = 100, multiply by O (0, 91). In this example, you actually only traveled 91 km.

• You can use the KPL to experiment with ways to increase fuel efficiency. For example, if you normally drive at an average speed of 100 km per hour, you can calculate your KPL and then drive at 55 KPH and measure it again; efficiency is likely to increase.
• To determine how the change in gas price will affect your budget, write down the number of miles you expect to drive in a week (or month or year) and divide by your KPL. Then multiply the answer by the price per liter of gasoline. By setting different prices, you can see how much more (or less) you will end up paying per week (or per month, or per year).
• The vast majority of cars come equipped with trip odometers, which is a value that takes mileage from a certain point and can be reset. This device is apart of the normal odometer, which counts the number of kilometers of the car from the beginning. You can use this device to count the kilometers. "Divide" the number of kilometers a full tank will give you by the tank capacity to get the vehicle's efficiency.
• Try to calculate your KPL more than once to get a more accurate measurement. If you travel more on the highway than on normal roads, then your KPL will be a bit higher. On the other hand, if you drive in a slow city (from stopping a lot), your KPL will be lower.
• To get your gas going, drive between 45 and 90 k / h. Not only will you get more gas mileage, but you will also extend the life of your vehicle and its auto parts.

## Warnings

• Mileage can vary in different driving patterns, while less braking and acceleration will give you better mileage. You'll see your mileage increase when you take road trips instead of a week of driving and braking on city streets.
• The calculations may not be exact. Repeat these steps 2-3 times and average the values to get a more accurate KPL.
• Miles per gallon is used in other countries. In the United States, gasoline is sold in gallons and they measure distances in miles so they use this measurement. In the UK there are also variations because it uses both the metric and imperialist systems to have measurements in gallons, liters, miles and kilometers.