Is a CNG conversion worth it
CNG cuts your fuel cost per kilometre by more than half, but a conversion kit costs money upfront and takes away boot space. The decision comes down to how quickly your driving recovers the kit cost.
Formula
Break-even km = kit cost ÷ (petrol cost per km − CNG cost per km)
- Petrol cost per km = price per litre ÷ km per litre
- CNG cost per km = price per kg ÷ km per kg
- Factory-fitted CNG needs no separate kit cost, only the variant premium
The saving per kilometre
Petrol at ₹105 a litre with 15 km/l costs ₹7 a kilometre. CNG at ₹80 a kg with 26 km/kg costs about ₹3.08 — a saving of roughly ₹3.90 for every kilometre.
Driving 1,500 km a month, that is about ₹5,900 saved monthly and ₹70,000 a year. For a taxi or a long-distance commuter the annual saving can exceed the cost of the kit itself.
When the kit pays for itself
A kit costing ₹70,000 is recovered after roughly 18,000 km. Someone driving 18,000 km a year breaks even in about twelve months; someone driving 6,000 km a year takes three years.
A factory-fitted CNG variant is usually the better route where available, because it carries a manufacturer warranty and does not void anything on the vehicle.
What you give up
The cylinder occupies most of the boot, which for many families is the real deal-breaker. Expect a modest reduction in power and pickup, and slightly higher engine maintenance since CNG runs hotter.
Refuelling takes longer and CNG stations are far less widespread than petrol pumps, so long routes need planning. Most CNG vehicles retain a small petrol tank as a fallback.
Compliance and paperwork
An aftermarket kit must be approved and the change endorsed on the registration certificate, and your insurer must be informed so the kit is covered. Cylinders require periodic hydro-testing, typically every three years.
Skipping these steps risks a rejected insurance claim and problems at resale. Some manufacturer warranties are also affected by an unapproved conversion.
Break-even on a ₹70,000 kit
- Petrol running cost
- ₹7.00 per km
- CNG running cost
- ≈ ₹3.08 per km
- Saving per km
- ≈ ₹3.92
- Kit cost
- ₹70,000
- Break-even distance
- ≈ 18,000 km
- Annual saving at 18,000 km
- ≈ ₹70,000
CNG suits high-mileage city driving where the boot is rarely needed. For occasional use or frequent luggage-heavy trips, the trade-offs outweigh the saving.