CNG vs diesel: cheaper to run, but at what cost?

CNG vs diesel running cost in India: cost per kilometre, yearly fuel spend, break-even distance, and the practical trade-offs for each fuel.

Updated 2026-08-04 · figures computed from the same engine as our fuel cost calculator

The short answer

CNG costs ₹2 less per kilometre to run than diesel — about ₹21,333 a year at 1,000 km a month. It is also no more expensive to buy, so there is no break-even to wait for.

Diesel

18 km/L · ₹89/L
₹5 / km

Better mileage and torque, but higher purchase premium, costlier servicing, and a 10-year NGT age cap in Delhi-NCR.

CNG

24 km/kg · ₹76/kg
₹3 / km

Cheapest running cost of any ICE option, but boot space is lost to the cylinder, power drops ~10%, and refuelling queues are long outside metros.

Running cost by how much you drive

Monthly drivingDieselCNGYou save
500 km
Light city use
₹2,472/mo
₹29,667/yr
₹1,583/mo
₹19,000/yr
₹10,667/yr
1,000 km
Average commute
₹4,944/mo
₹59,333/yr
₹3,167/mo
₹38,000/yr
₹21,333/yr
1,500 km
Heavy commute
₹7,417/mo
₹89,000/yr
₹4,750/mo
₹57,000/yr
₹32,000/yr
2,500 km
Very high / commercial
₹12,361/mo
₹1,48,333/yr
₹7,917/mo
₹95,000/yr
₹53,333/yr

Fuel/energy cost only. Servicing, insurance and depreciation differ too — use the true cost of ownership calculator for the full picture.

Run your own numbers → Full 5-year cost calculator

Common questions

Is CNG cheaper than diesel in India?

CNG is cheaper both to buy and to run in this comparison — at ₹2 less per kilometre, there is no break-even to wait for.

What is the running cost per kilometre of diesel vs cng in India?

At ₹89/L and 18 km/L, diesel costs about ₹5 per km. CNG at ₹76/kg and 24 km/kg costs about ₹3 per km. That is a difference of ₹2 per kilometre, or ₹21,333 a year at 1,000 km a month.

How much can I save a year with cng over diesel?

At 1,000 km a month you save about ₹21,333 a year. At 1,500 km a month it is roughly ₹32,000, and at 2,500 km a month about ₹53,333. These are fuel/energy costs only — servicing and insurance differences are on top.

What are the downsides of cng?

Cheapest running cost of any ICE option, but boot space is lost to the cylinder, power drops ~10%, and refuelling queues are long outside metros.

Other comparisons

Petrol vs Diesel →Petrol vs CNG →Petrol vs Electric (EV) →Diesel vs Electric (EV) →CNG vs Electric (EV) →

Prices are indicative all-India averages and move daily — Delhi, Mumbai and Bengaluru typically differ ₹2–5 per litre from the national average. Mileage figures are realistic city-driving estimates, not ARAI claims.