Ask literally anyone what their car costs to run and nine out of ten times, they’ll just tell you the mileage. “I get 18 kmpl, so it’s cheap.” That’s it. That’s the whole answer people give.
Which, honestly, isn’t wrong exactly — it’s just incomplete in a way that can cost you real money. Mileage only tells you about fuel. It says nothing about the insurance renewal you conveniently forget about every year, the service bill that always seems to be bigger than expected, tyres wearing out, or the depreciation quietly eating into your car’s value while you’re not looking. Add all that up and it’s usually a bigger number than fuel by itself.
So if you actually want to know how to calculate car running cost properly — like, the number that tells you what the car is costing you every month, not just at the pump — here’s the full thing, broken down.
Mileage Alone Is Kind of Misleading, Honestly
Two cars can have the exact same mileage and still cost completely different amounts to run. One has cheap, easy-to-find spare parts and a ₹500 service bill. The other needs a part flown in from a dealership two cities away because nobody stocks it locally. Same mileage, very different reality.
Real running cost has five parts to it, and mileage is only one:
- Fuel or energy cost
- Scheduled maintenance and servicing
- Insurance premium
- Depreciation
- The small stuff — tyres, tolls, parking, minor repairs
Let’s go through them one by one.
1. Fuel Cost Per Km
Easiest one to work out, and it’s usually where people stop.
Fuel cost per km = current fuel price ÷ real-world mileage (not the number on the brochure)
That “real-world” part matters a lot. ARAI mileage figures are tested in ideal lab conditions — no traffic, no AC running, no aggressive acceleration, basically nothing like actual Indian roads. Real mileage in city traffic usually ends up 15-25% lower than what’s claimed.
So a car rated at 20 kmpl might realistically give you 15-16 kmpl once you’re stuck in actual traffic. At ₹105/litre, that’s about ₹6.6-7/km, not the ₹5.25/km the brochure wants you to believe.
For current fuel prices in your city, the Petroleum Planning & Analysis Cell has the official government numbers — better than relying on whatever price you remember from three months ago.
2. Maintenance Cost Per Year
This covers services, filters, oil, brake pads — all the stuff that doesn’t show up until the bill lands in your hand.
Rough yearly numbers for a petrol car:
- Budget hatchback: ₹8,000 – ₹15,000
- Mid-size sedan/SUV: ₹15,000 – ₹25,000
- Premium segment: ₹30,000 and up, sometimes way up
Divide that by how many km you drive a year and you get a per-km maintenance number. Drive 15,000 km a year with ₹15,000 in maintenance, that’s exactly ₹1/km added — a number almost nobody factors in when they’re comparing cars on mileage alone.
3. Insurance, Spread Over the Year
Insurance is fixed no matter how much you drive, which is exactly why low-mileage owners often think their car is “cheap” when it actually isn’t — the fixed costs just hit harder per km when you’re not driving much.
Insurance cost per km = annual premium ÷ km driven that year
A ₹12,000 premium on 8,000 km a year works out to ₹1.5/km. The same premium spread over 20,000 km a year is only ₹0.6/km. Same car, same premium — different real cost, just because of how much you drive it.
4. Depreciation — The One Nobody Wants to Talk About
This is genuinely the biggest hidden cost in owning a car, and almost nobody counts it when they talk about “running cost.”
Cars typically lose 15-20% of their value in the first year alone, then roughly 10% a year after that. Say you bought a car for ₹10 lakh and it’s worth ₹6 lakh four years later. That’s a ₹4 lakh loss, spread over maybe 48,000-60,000 km of driving — which works out to something like ₹7-8/km. Read that again. That’s often more than what you spent on fuel.
Depreciation per km = (purchase price − expected resale value) ÷ total km driven
If you’re still choosing between cars, our Car Reviews section usually points out which models actually hold their value in a segment, which honestly matters more than the mileage figure most people obsess over.
5. The Small Stuff That Sneaks Up on You
- Tyres — replaced roughly every 40,000-50,000 km, ₹2,000-5,000 each depending on the car
- Tolls and parking — easy to ignore but adds up fast for daily commuters
- Odds and ends — wiper blades, a new battery every 3-4 years, AC servicing when it stops cooling in summer
None of these are huge on their own, but together they usually add ₹0.5-1.5/km depending on how you use the car.
Okay, Here’s the Full Formula
Put it all together:
Real cost per km = fuel/energy cost + (annual maintenance ÷ annual km) + (annual insurance ÷ annual km) + (depreciation ÷ total km) + miscellaneous costs
A Worked Example — Petrol Hatchback, 12,000 km/year, Held for 5 Years
| Component | Cost/km |
|---|---|
| Fuel (real-world mileage) | ₹6.50 |
| Maintenance | ₹1.00 |
| Insurance | ₹0.90 |
| Depreciation | ₹6.50 |
| Miscellaneous | ₹0.80 |
| Total real running cost | ₹15.70/km |
Compare that to the ₹6.50/km most people quote based on fuel alone, and you can see the gap. “Cheap to run” and “actually cheap” turn out to be two very different claims.
This is basically the same math we used when we compared fuel types head-to-head — if you’re stuck between petrol, CNG, and electric, our petrol vs CNG vs EV total cost of ownership piece runs the exact same formula across all three.
How to Actually Use This
- Comparing two cars before buying? Run both through this using your real expected annual km, not some round number you guessed.
- Wondering whether to sell your current car? Depreciation slows down a lot after year 4-5, so an older car’s real running cost per km is often lower than people assume — as long as maintenance hasn’t gone off the rails.
- Trying to budget monthly? Multiply your real cost per km by your usual monthly distance. Far more honest than just looking at the fuel bill.
FAQs
What’s a decent running cost per km for a car in India? For a budget hatchback over 5 years, somewhere between ₹10-14/km is typical once depreciation is included. Premium and luxury cars often cross ₹20/km once you factor in parts and faster depreciation.
Does running cost include the EMI? No. EMI is a financing cost, not an ownership cost. Two people buying the exact same car — one on loan, one paying cash — have the same running cost, just different monthly outflows.
Why doesn’t my car ever hit its ARAI mileage? Because ARAI numbers come from lab testing — no traffic, no AC, gentle driving. Real city traffic usually knocks 15-25% off that figure.
Want to figure out your car budget before you even start comparing models? Check out how your salary decides your car budget — good place to start.
