One of the joys of an electric car is that “filling up” is cheaper — but because you charge in bits, at home and in public, at different prices, it’s easy to lose track of what you’re actually spending. Here’s how to measure your true EV running cost.
The two numbers that matter
- Cost per kWh — what you pay for electricity. This varies a lot by where and how you charge.
- Cost per km (or per mile) — total charging cost divided by distance. This is the honest measure of what driving costs, and it’s directly comparable to a petrol car’s cost per km.
Home vs public: the price gap is big
Where you charge changes the maths dramatically. In 2025:
- Home charging averaged around $0.17/kWh (~₱10) — roughly 6 cents per mile.
- Public charging averaged around $0.37/kWh (~₱23) (AAA) — roughly 13 cents per mile, with DC fast charging often $0.40–$0.65/kWh (~₱24–₱40).
Home overnight charging is commonly about three times cheaper than a fast charger on a road trip. So your mix of home and public charging, not just your car, determines your cost per km. (Dollar figures are US 2025 averages; peso equivalents use an approximate ₱61 = US$1, and your local electricity tariff may differ — plug in your own rate.)
How to calculate it
Method 1 — from the charge: note the kWh added (your charger, app, or car usually shows this) and multiply by your rate. Divide by the distance driven since the last charge.
Example: 30 kWh added at $0.17/kWh = $5.10 (
₱310). If that took you 180 km, that’s about **$0.028 (₱1.70) per km**.
Method 2 — from efficiency: if your car reports kWh per 100 km (say 16), multiply by your rate ($0.17) → about $2.72 per 100 km (~₱166), or roughly $0.027 (~₱1.60) per km.
As with fuel, one charge is rough; averaging several is accurate — especially if you mix home and public charging.
Track it, don’t guess it
This is the electric equivalent of logging fuel. The fuel & mileage tracking feature works the same way for charging: log the energy added, the price, and your odometer, and Kotselog turns it into your cost per km and a running total, so you can see your real saving and spot when public charging is quietly inflating the bill. It works offline at the charger, too. Open the app and log your first charge.
Your charging cost is one line in your overall cost of ownership — and for EV owners it’s usually the pleasant one.
Read next
- PHEV explained: how plug-in hybrids work and their real running costs
- How to track fuel economy (MPG and km/L) — the petrol equivalent
- Switching to an EV: a new owner’s checklist
- EPA vs WLTP vs NEDC — why your real efficiency rarely matches the brochure figure, and roughly how to convert between the standards
Frequently asked questions
How do I calculate my EV's cost per km?
Take the electricity you used to charge (in kWh) and multiply by your rate per kWh to get the cost, then divide by the distance driven on that charge. Or work out your car's efficiency (kWh per 100 km) and multiply by your electricity rate. Averaging several charges gives the most reliable figure.
Is it cheaper to charge at home or in public?
Home is almost always cheaper. In 2025, US home charging averaged about 17 cents per kWh — roughly ₱10 per kWh at ≈₱61 = US$1 — while public charging averaged about 37 cents (~₱23) per kWh; DC fast charging is the most expensive. Home overnight charging can be roughly three times cheaper than a fast charger. Local electricity prices vary a lot by country, so use your own per-kWh rate.
How much does charging an EV cost compared to petrol?
For most drivers charging at home, running an EV costs noticeably less per kilometer than fuelling a comparable petrol car — often less than half. Public fast charging narrows the gap. Tracking your own cost per km is the only way to know your real saving.
How Kotselog helps: Log fill-ups in seconds and see your real mileage — km/L or MPG — over time. See the fuel economy feature →
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