CNG vs Petrol: Cost and Mileage Comparison

Introduction

In an age where rising fuel prices and environmental concerns are changing consumer decisions, the choice between CNG (Compressed Natural Gas) and petrol-powered vehicles has become increasingly significant for Indian car buyers. Here is CNG vs Petrol: Cost and Mileage Comparison With the auto industry leaning toward greener and other economical options, CNG cars are seeing a sharp rise in popularity, particularly among urban daily travellers and cost aware drivers.

This detailed guide will help you understand the key differences between CNG and petrol vehicles, focusing on the most important deciding factors: cost and mileage. We’ll break down initial purchase price, running costs, fuel efficiency, long-term savings, and actual use cases to help you make a good choice.

What is CNG and How Does It Work?

Compressed Natural Gas (CNG) is a fossil fuel replacement for petrol, diesel, and LPG. It consists mainly of methane and is stored in high-pressure tanks in a gaseous state. It is considered to be a much cleaner and more economical alternative to old fuels.

CNG vs Petrol Cost and Mileage Breakdown

1. Initial Purchase Cost

Fuel Type	Vehicle Cost (Approx.)
Petrol	Lower
CNG	Rs. 70,000 – 1,00,000 more than petrol variants

• CNG cars are typically more expensive at the begining due to the additional CNG kit and its parts. However, this is a one-time cost.
• For example, a Maruti Suzuki WagonR petrol version starts at around Rs. 5.5 lakh, while the CNG variant starts at Rs. 6.4 lakh.

2. Fuel Price Comparison

Fuel Type	Price per Kg/Litre (May 2025, India Avg.)
Petrol	Rs. 105 per litre
CNG	Rs. 79 per kg

• CNG is slight cheaper than petrol, making it the economical choice for daily travellers.
• As petrol prices continue to rise, CNG becomes even more popular.

3. Mileage: CNG Mileage vs Petrol Mileage

Fuel Type	Mileage (km/kg or km/litre)
Petrol	17–21 km/litre
CNG	22–32 km/kg

• CNG cars offer good mileage, especially for city driving.
• The WagonR CNG, for example, gives up to 34.05 km/kg, while its petrol similar version offers around 21.79 km/l. Top 5 cng cars in 2025 is here!!!

4. Running Cost Per Kilometer: CNG Car vs Petrol Car Running Cost

Fuel Type	Cost per Km (Approx.)
Petrol	Rs. 5.00 – Rs. 6.00
CNG	Rs. 2.50 – Rs. 3.00

• CNG cuts down your running cost by nearly half.
• Ideal for people with daily travellers, more than 30 km.

Advantages of CNG Cars

1. Low Running Costs: With fuel being cheaper and more efficient, CNG cars save can your money.
2. Eco-Friendly: Release lower CO2 and nitrogen oxides; contributes to cleaner air.
3. Lower Maintenance (for engine): Cleaner combustion results in less engine wear.
4. Dual Fuel Option: Most CNG cars allow switching back to petrol if needed.

Disadvantages of CNG Cars

1. Higher Initial Cost: Additional cost of factory-fitted or upgraded kits.
2. Less Boot Space: CNG cylinder takes up luggage space.
3. Slight Power Drop: CNG vehicles generally produce slightly less power.
4. Limited Refuelling Infrastructure: CNG pumps are still not as everywhere, especially in rural areas.

Advantages of Petrol Cars

1. Better Power and Acceleration: Good for highway driving or performance-focused users.
2. Lower Initial Cost: Great for occasional users or low budget customer.
3. Availability: Petrol is available across the country.
4. No Boot Compromise: Full storage space.

Disadvantages of Petrol Cars

1. High Fuel Cost: Fuel prices have been on the rise continuously.
2. Lower Mileage: Compared to CNG, petrol cars are less fuel-efficient.
3. Higher Emissions: More harmful to the environment.

Real-Life Use Case Scenarios

Scenario 1: City Daily Traveller Driving 40 Km Daily

• Petrol Car: Monthly fuel cost = Rs. 6,000 – Rs. 7,200
• CNG Car: Monthly fuel cost = Rs. 3,000 – Rs. 3,600
• Annual Savings with CNG: Rs. 36,000 – Rs. 43,200

Scenario 2: Occasional Weekend Driving

• Petrol may be better for users driving less than 500 km/month due to lower cost in the beginning and wider fuel availability.

Scenario 3: Intercity Commercial Use (e.g., taxi drivers)

• CNG clearly wins, with high mileage and low per-km cost translating into big savings.

Maintenance Comparison

Aspect	Petrol Cars	CNG Cars
Engine Wear	Moderate	Low
Spark Plug Life	Longer	Shorter
Service Cost	Standard	Slightly higher
Kit Maintenance	N/A	Required every 20,000 km

Environmental Impact

• CNG vehicles release ~25% less CO2 than petrol vehicles.
• Lower levels of carbon monoxide, hydrocarbons, and nitrogen oxides.
• Reduces overall carbon impact, matching with India’s clean energy target.

Conclusion: Final Decision on CNG vs Petrol

Choosing between a CNG and petrol vehicle is depended to your driving habits, budget, and priorities.

• If you’re looking for long-term savings, daily traveller, and environmental responsibility, CNG cars are the better option.
• If you prioritize performance, flexibility, or limited usage, petrol cars may still suit you better.

Final Recommendations:

• Best for Daily Travellers: CNG
• Best for Occasional Drivers: Petrol
• Best for Taxi or Commercial Use: CNG