Ask someone what their car costs and they will usually tell you what they spend on fuel. But fuel is often less than half of it. Insurance, servicing, tyres, road tax and parking all count too, and they come in lumps that are easy to forget.
Cost per km puts all of it into one number.
The formula
Cost per km = everything you spent on the car ÷ the distance you drove
Use the same period for both: a month, a year, or everything since you started keeping track. Take the distance from the odometer at the start and at the end.
What to count
- Energy: petrol, diesel, or charging.
- Servicing and repairs: oil changes, brake pads, a new battery.
- Tyres.
- Insurance and road tax.
- Parking and tolls.
- Everything else: car washes, fines, accessories.
A worked example
These figures are made up to show the sum. Yours will be different.
| Cost over one year | Amount |
|---|---|
| Petrol | RM 3,000 |
| Servicing | RM 600 |
| Tyres | RM 800 |
| Insurance | RM 1,500 |
| Road tax | RM 90 |
| Parking and tolls | RM 1,200 |
| Total | RM 7,190 |
The car drove 15,000 km that year.
- Cost per km: 7,190 ÷ 15,000 = RM 0.48 per km
- Fuel alone: 3,000 ÷ 15,000 = RM 0.20 per km
So fuel was less than half of what the car really cost to drive. A 10 km trip to the shops cost RM 4.80, not RM 2.
Why per km, and not per month?
A monthly total goes up when you drive more, so it can't tell you whether the car got more expensive or you just used it more. Cost per km can. It also compares cars that are nothing alike: a petrol hatchback and an electric SUV each end up with one figure in the same unit.
Should you include the price of the car?
What you have covered so far is the running cost. It answers "what does it cost to keep this car on the road?"
There's a second, bigger number: what the car itself costs you as it loses value. As a rough example, a car bought for RM 60,000 and sold for RM 30,000 five years and 75,000 km later has lost RM 30,000. That's another RM 0.40 per km on top of the running cost.
Both numbers are useful. Use the running cost to compare months or to spot a bill that went up. Use the one with the purchase price when deciding whether to buy, keep or replace a car.
Tips
- Start from today. Note the odometer now and log from here. You don't need last year's receipts.
- Give it a few months. Insurance and road tax come once a year. If you pay insurance in your first month, the cost per km will look huge until the distance catches up. That's the maths working as it should.
- Keep every receipt. Small costs like parking add up. They're usually what surprises people most.
How OdoTick does it
OdoTick is built around this number. Log fill-ups, charges and any other bill, and it shows your cost per km on the home screen. You can see it for running costs alone or with the purchase price included, for petrol, diesel, electric and hybrid cars alike. Until the odometer has moved past your first reading, it shows a dash instead of a guess.