Thinking about switching from a CNG car to an electric one, or choosing between the two before you buy? Money spent at the pump or the charger usually decides it. This CNG vs EV cost calculator shows you the running cost of each, per kilometre and over any distance you pick, using your own local prices.
You enter a few numbers, and it tells you which option is cheaper to drive and by how much. No guesswork, no sales pitch, just the maths on fuel and electricity.
An electric car is usually cheaper to run than a CNG car in India when you charge at home. Home charging costs roughly ₹1–1.5 per km, while a CNG car costs about ₹3–5 per km. The gap shrinks if you rely on public fast charging, where EV costs can match or beat CNG only slightly.
CNG vs EV Cost Calculator
CNG vs EV Cost Calculator
Compare the running cost of a CNG car and an electric car per kilometre, and see which is cheaper for your driving.
Distance over which to compare, e.g. your monthly kilometres.
Enter a distance greater than 0.
Your local CNG rate. Around ₹85–90/kg in most cities.
Enter a CNG price greater than 0.
Your CNG car’s ARAI or real-world mileage.
Enter a mileage greater than 0.
Home rate is usually ₹6–10. Public DC fast charging is ₹15–25.
Enter a tariff greater than 0.
Real-world distance per unit. Most EVs do 6–7.5 km/kWh.
Enter an efficiency greater than 0.
Energy lost while charging. Leave blank to use 8%.
Fill in 5 more required fields to calculate.
Cost per kilometre
Total cost
This tool compares the day-to-day running cost of a CNG car and an electric car. It does not compare the on-road price, servicing, or resale value – only what you spend to move each kilometre.
What you enter:
- Distance you want to compare, such as your monthly kilometres
- CNG price in your city (₹ per kg)
- Your CNG car's mileage (km per kg)
- Your electricity tariff (₹ per kWh)
- Your EV's efficiency (km per kWh)
- Charging loss as a percentage (optional; 8% is used if left blank)
What you get back:
- Cost per kilometre for both CNG and EV
- Total cost for the distance you entered
- How much you save (or spend extra) with the EV
- A clear verdict on which is cheaper and by what percentage
It suits anyone weighing a CNG car against an EV, current CNG owners curious about switching, and fleet or cab drivers who track cost per km closely. Use it whenever CNG or electricity prices change, or when you're comparing two specific cars.
CNG vs EV: Running Costs at a Glance
Before you run your own numbers, here's a rough picture of what each option costs per kilometre in India today. Your exact figures depend on local prices and how you drive.
| Option | Typical cost per km | Notes |
|---|---|---|
| EV, home charging | ₹1 – ₹1.5 | Cheapest option; needs a home charging point |
| EV, public DC fast charging | ₹2.5 – ₹4 | Convenient, but far pricier per unit |
| CNG car | ₹3 – ₹5 | Depends heavily on the car's mileage |
Home charging is where an EV pulls clearly ahead. Once you lean on public fast charging, the two options get much closer.
The Formula Behind the Calculator
The idea is simple: work out what each vehicle spends to travel one kilometre, then multiply by your distance.
CNG cost per km = CNG price (₹/kg) ÷ CNG mileage (km/kg)
EV cost per km = [Electricity tariff (₹/kWh) × loss factor] ÷ EV efficiency (km/kWh)
The loss factor accounts for energy wasted while charging. It equals 1 + (charging loss % ÷ 100). At 8% loss, the factor is 1.08.
Total cost = cost per km × distance
EV savings % = (CNG cost per km − EV cost per km) ÷ CNG cost per km × 100
What each variable means
| Variable | Unit | What it is |
|---|---|---|
| CNG price | ₹/kg | Retail CNG rate at your local station |
| CNG mileage | km/kg | Distance your CNG car covers on 1 kg |
| Electricity tariff | ₹/kWh | What you pay per unit of electricity |
| EV efficiency | km/kWh | Distance your EV covers on 1 unit |
| Charging loss | % | Energy lost between the socket and the battery |
A worked example
Say you drive 1,500 km a month. Your CNG car returns 25 km/kg, and CNG costs ₹90/kg. Your EV does 7.2 km/kWh, and you charge at home at ₹8/kWh with an 8% charging loss.
- CNG cost per km = 90 ÷ 25 = ₹3.60
- EV cost per km = (8 × 1.08) ÷ 7.2 = 8.64 ÷ 7.2 = ₹1.20
- CNG cost for 1,500 km = 3.60 × 1,500 = ₹5,400
- EV cost for 1,500 km = 1.20 × 1,500 = ₹1,800
- Monthly saving = 5,400 − 1,800 = ₹3,600
The EV works out about 67% cheaper to run. Over a year, that's roughly ₹43,200 saved on the same driving.
How to Read Your Result
The calculator shows your saving as a percentage. Here's what the ranges mean.
| EV savings vs CNG | Verdict | What it usually means |
|---|---|---|
| 30% or more | EV clearly cheaper | You charge at home at a normal tariff. The EV wins comfortably. |
| 0% to 30% | Close call | Costs are similar. Often caused by pricier charging or lower EV efficiency. |
| Below 0% | CNG cheaper | Usually a high electricity rate (public fast charging) or a very efficient CNG car. |
Most home-charging owners land in the green band. The result only tips toward CNG when you enter a public DC fast-charging rate, which runs far higher than a home tariff.
Common Mistakes to Avoid
- Treating ARAI mileage as real-world. Lab figures are optimistic. Real CNG mileage and EV efficiency are usually 15–25% lower, so use your own averages when you can.
- Mixing best case with worst case. Don't compare a cheap home charge against the most efficient CNG car, or public fast charging against a thirsty one. Keep both figures fair.
- Ignoring charging losses. Some energy is lost while charging. Skipping it makes the EV look slightly cheaper than it really is.
- Forgetting efficiency drops. Heavy AC use, highway speeds, and city traffic all lower both CNG mileage and EV range. Adjust for how you actually drive.
- Judging the whole cost from running cost alone. This tool compares fuel and electricity only. Purchase price, servicing, and battery life matter too.
Practical Tips
- Pull your real mileage from your last few fill-ups instead of the brochure number.
- Charge overnight and check whether your DISCOM offers a time-of-day or EV tariff – it can cut your rate further.
- If you can't charge at home, enter the public rate you'll actually pay so the result stays honest.
- Re-run the numbers whenever CNG or electricity prices change, since both move over time.
- Compare two specific cars by entering each one's real efficiency, not a generic figure.
Summary
| Item | Detail |
|---|---|
| Inputs | Distance, CNG price, CNG mileage, electricity tariff, EV efficiency, charging loss |
| Core formula | Cost per km = fuel/energy price ÷ efficiency |
| Outputs | Cost per km, total cost, savings, cheaper option |
| Best used for | Comparing CNG and EV running costs before buying or switching |
Frequently Asked Questions
Is an EV really cheaper to run than a CNG car in India?
In most home-charging cases, yes. A home charge costs around ₹1–1.5 per km against roughly ₹3–5 per km for CNG. The advantage narrows if you depend on public fast charging.
What electricity rate should I use?
Use your home tariff, usually ₹6–10 per unit depending on your state and slab. For public charging, enter the operator's rate, which is often ₹15–25 per unit at DC fast chargers.
Does public charging change the result?
A lot. Public DC fast charging can cost three to four times your home rate. At those prices, an EV's running cost can rise close to a CNG car's, so enter the rate you'll really use.
What EV efficiency is realistic?
Most electric cars in India return about 6–7.5 km per kWh in real driving. Smaller cars can do more, larger SUVs less. Traffic, speed, and AC all pull the figure down.
Does this include the car's price or servicing?
No. This calculator compares running cost only – what you spend on CNG versus electricity. Purchase price, insurance, servicing, and battery replacement are separate costs worth checking too.
How much can I save per year by switching from CNG to EV?
It depends on your distance and rates. Driving 1,500 km a month with home charging, savings often land around ₹35,000–45,000 a year. Higher mileage means bigger savings.
Why include a charging loss?
Some energy is lost as heat while charging, so the battery stores a little less than the meter records. An 8% loss is a fair default and keeps the EV cost realistic.
Is CNG ever cheaper than an EV?
It can be. If you charge mostly at expensive public stations, or your EV is inefficient while your CNG car is very economical, CNG can come out ahead. The calculator will flag this.
The Bottom Line
For most drivers who can charge at home, an electric car costs clearly less per kilometre than a CNG car, and the savings add up fast over a year. The picture changes with public charging, so the honest answer depends on your own rates and driving.
Enter your numbers above to see exactly where you stand and how much you could save.
Sources
- Automotive Research Association of India (ARAI) – official mileage and efficiency certification: araiindia.com
- Indraprastha Gas Limited (IGL) – CNG prices in Delhi-NCR: iglonline.net
- Mahanagar Gas Limited (MGL) – CNG prices in Mumbai: mahanagargas.com
- Central Electricity Authority (CEA) – electricity and power data: cea.nic.in
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