Petrol and diesel at fuel pump

Petrol vs Diesel: Efficiency and Cost of Running

Deciding between petrol or diesel power is one of the very first decisions you will have to make before purchasing a new or even a pre-owned car. Wondering what is going to be the most suitable type of fuel for your upcoming vehicle, is a question that has haunted many. Each has its own pros and cons. For years, the difference between diesel and petrol prices have been a primary reason for buyers to opt for the former, but recently, diesel prices have not only matched but also often surpassed petrol prices. Even then, petrol vs. diesel is far more complex than it seems, so if you are wondering what’s better for you, then here’s everything you need to make an informed decision.


When it comes to efficiency, diesel engines provide more efficiency by using 15-20% less fuel compared to petrol engines. The low-end torque of diesel engines provide a much better highway driving experience. However, the price of this efficiency is a higher premium compared to the petrol variant of the same car. Parts and components for diesel cars are usually also more expensive due to the complex construction of diesel engines.

On the other hand, petrol cars cost less compared to their diesel counterparts due to less complex components. Petrol engines tend to run quieter than diesel engines and service costs are also generally lower than diesel cars. However, petrol engines tend to consume more fuel, leading to lower fuel efficiency and higher fuel costs.

Cost of Running

Now that you have a fair idea about a few crucial factors that are unique to each fuel, here are some key factors to consider before deciding the fuel type for your new car:

Up-Front Price Difference

Although the price gap between diesel and petrol models isn’t as wide as it used to be, there still is a considerable difference between the two. To have a general idea about both the fuels, here is a little insight on the petrol-diesel differences between the petrol and diesel variants of the new Tata Altroz:

Tata Altroz petrol vs diesel price comparison

As evident, the up-front price difference between the petrol and diesel Tata Altroz cars is as much as ₹1.61 lakhs, in favour of the petrol variant. The diesel variants of many cars command a higher premium over their petrol counterparts.

However, in the used car market, the up-front price difference between petrol and diesel tends to be closer for the same car with similar kilometers driven. Comparing the prices of petrol and diesel variants of used Hyundai Creta, we find that the price difference comes down to just ₹40,000. The diesel variant still costs higher due to diesel cars generally depreciating less than their petrol counterparts

Mileage Game

Mileage is another factor that Indians obsess about before even looking for the perfect vehicle. When it comes to mileage, diesel engines tend to outdo petrol ones. For example if we consider the Tata Altroz the ARAI claimed efficiency of the petrol manual is 19.05 kmpl while for diesel it is 25.11 kmpl. This translated to a difference of about 6.06 kmpl. 

Tata Altroz

With fuel prices generally rising over the last few years, the higher price of petrol combined with the lower mileage offered by petrol engines, makes them less value for money when it comes to efficiency.

Let’s say you use your Tata Altroz to commute around 25 km daily with fuel prices being constant. On the Altroz petrol, your cost of running would be Rs. 122 per day (based on a petrol price of ₹93) and the same cost of running on the Altroz diesel would be Rs. 82 per day (based on diesel price of Rs 83). This translates to a monthly expenditure of Rs. 3660 for petrol and Rs. 2460 for diesel. In essence, the diesel variant will save you ₹1200 per month and around ₹14400 in a year.

Service and Maintenance Cost

Service and maintenance cost is another crucial factor to consider before choosing your preferred fuel option. Unlike petrol engines which operate on spark plugs, diesel engines solely rely on compression to ignite the fuel. Because of this, the forces that are generated on the components are very high. This is one of the many reasons why diesel cars undergo excessive wear and tear. Moreover, since the price of components used on a diesel engine is relatively higher, the overall service cost of a diesel engine is generally higher than what is offered on petrol. 

Maintenance cost for a diesel is about 50% more expensive than that of petrol. To have a better idea about the same, let us take the example of the Tata Altroz again. The service cost of the petrol and diesel variants of the Tata Altroz for 4 years are detailed below:

Tata Altroz Maintenance Charges




1st Year



2nd Year



3rd Year



4th Year



Total Costs



After 4 years, the total running cost in terms of servicing is ₹28,289 for the diesel Tata Altroz and ₹34,079 for the petrol Tata Altroz. The diesel Altroz comes out to be ₹1500 more expensive per year than the petrol variant. The savings made on fuel more than offsets the additional service costs incurred.

Insurance Premium

Another key aspect to consider is Insurance premium. Speaking as per the trend, diesel cars tend to have higher insurance premium in later years with marginally higher risk cover in comparison to petrol cars.

  • For cars where the ex-showroom price difference is upto ₹50,000: Expect cumulative insurance premium to be higher by ₹10,000 over a span of 7 years.
  • For cars where the ex-showroom price difference is ₹1.25 lakh to ₹1.5 lakh: Expect insurance premium to be Rs 20,000 more over a span of 7 years.

The Bottom Line

To summarize the scenario of the petrol vs. diesel debate, taking a practical example would be the best. So let us consider the example of the Tata Altroz which is priced at ₹6,38,000 (on-road Delhi) for the base petrol version and ₹7,99,000 (on-road Delhi) for the diesel counterpart. The difference of price paid up-front in favour of petrol comes out to be ₹1,61,000. 

Now let’s calculate how many years it would take one to cover up the additional cost paid upfront if you happen to buy the diesel variant. Considering an average running of 15,000 km with a Tata Altroz, you can expect the following running costs for the petrol and diesel variants respectively:

Tata Altroz Cost of Running for 4 Years

Yearly Running



Fuel Efficiency



Fuel Price



Yearly Fuel Costs



Total Fuel Costs



Total Maintenance Costs



Total Costs After 4 Years



If you plan to only drive less than 15000 km in a year and own the car for less than 5 years, diesel cars are the more expensive option to own. However, if your driving requirements are more than 15000 km in a year or you plan to own the car for more than 5 years, diesel cars provide better value for money in the long run.

So, basically to nullify the difference in on-road price (₹1.61 lakh) paid up-front, one would have to own the car for more than five and a half years. This is more than half of a diesel vehicle’s life, so basically if your car covers an average annual mileage less than 10,000 kilometres per year, it’s good to go with a petrol vehicle, since you might require over 6 to 7 years to cover up the cost otherwise.

If you plan to only drive less than 15000 km in a year and own the car for less than 5 years, diesel cars are the more expensive option to own. However, if your driving requirements are more than 15000 km in a year or you plan to own the car for more than 5 years, diesel cars provide better value for money in the long run. Thus, for long distance drivers, diesel engines are the smarter choice, while for those who love taking out their vehicle every once a while, petrol is a smarter choice.

FAQs about Petrol vs Diesel Car

Q. Which is more efficient petrol or diesel engine?

A. A diesel engine is more efficient as it provides more mileage compared to petrol engines.

Q. Should I buy a diesel car for city driving?

A. For low mileage driving in the city, a diesel car is not recommended. Diesel cars only offer great value if your driving features regular highway driving or more than 15,000 km per month.

Q. What is the advantage of a petrol car?

A. A petrol car is usually much cheaper than the equivalent diesel model. Petrol cars are also more suited for regular city driving with less than 10,000 km driven in a year.

Q. Will diesel cars be banned in India?

A. While the Delhi government has banned the sale of diesel cars in the state, diesel cars in the rest of India have not been banned. With the introduction of cleaner BS6 diesel engines, diesel cars will not be banned in the near future.

Q. How do I choose between petrol and diesel cars?

A. This depends entirely on your usage. If you regularly drive long distances, then a diesel car will fit your lifestyle and provide savings in fuel. However, if your driving is mostly in the city, then a petrol car will provide more value to you.

Important Links

Used Petrol Cars in Delhi-NCR | Used Petrol Cars in Bangalore | Used Petrol Cars in Hyderabad | Used Petrol Cars in Pune | Used Petrol Cars in Mumbai | Used Diesel Cars in Delhi-NCR | Used Diesel Cars in Bangalore | Used Diesel Cars in Hyderabad | Used Diesel Cars in Pune | Used Diesel Cars in Mumbai

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