The Cost of Charging an Electric Car at Home: How Much per Kilometre?
The first question everyone asks before buying an electric car is this: "If I charge at home, what will it really cost me?" The good news is that this calculation is far simpler than people think. In this guide we show you step by step how to work out the cost of charging an electric car at home per kilometre, and explain how to compare it with a petrol car. All the numerical examples are hypothetical; you will find your own exact figure by substituting the current unit price from your own bill.
The basic formula for charging cost
The cost of charging at home comes down to a single multiplication: you multiply the energy you use (kWh) by the unit price of electricity (TL/kWh). For example, if 40 kWh went into the battery and the unit price is X TL/kWh, the cost of that charge is 40 × X TL. To find the cost per kilometre, all you need to know is how many kWh the car uses per 100 km.
- The cost of one charge = Energy used (kWh) × Unit electricity price (TL/kWh)
- Cost per kilometre = (The car's consumption in kWh/100 km ÷ 100) × Unit electricity price (TL/kWh)
- Cost for 100 km = Consumption (kWh/100 km) × Unit electricity price (TL/kWh)
How many kWh does your car use per 100 km?
The average energy consumption of electric cars is generally between 15 and 22 kWh per 100 km. Compact, efficient models sit near the lower end, while large SUVs and high-speed motorway driving run near the upper end. You can read the exact value from the average consumption display on your car's screen, shown as "kWh/100 km". In winter, consumption rises somewhat because of cabin heating and the battery's need to warm up; it is worth allowing for that margin in your calculation.
Do not forget the charging losses (~10%)
The energy you draw from the socket is slightly more than the energy that goes into your battery. The difference is lost as heat in the cable, the converter and the battery management. In home AC charging this loss is around 10%. So, after calculating the energy the car uses, multiplying the result by roughly 1.1 (or adding 10%) gives a more accurate cost, reflecting the real consumption that shows up on the bill. It may look like a small difference, but for a driver covering thousands of kilometres a year it adds up noticeably.
The multi-rate tariff in Türkiye: why is night charging cheap?
In Türkiye, residential customers can choose a multi-rate (three-rate) tariff instead of a single-rate one. In this tariff the day is divided into three periods: daytime, evening peak (the period of heaviest consumption, with the highest unit price) and night. The night period is markedly the cheapest. For an electric car owner this is a real opportunity: when you plug the car in on arriving home in the evening and let the charge fall into the night period, you buy the same energy at a much lower unit price.
- Daytime period: a mid-level unit price, for use during the day.
- Peak (evening) period: the highest unit price; avoid timing your charge for these hours where possible.
- Night period: the lowest unit price; the ideal window for car charging.
- The hours of the periods may vary by distribution company; confirm the current times from your bill or your distribution company.
You do not have to keep track of the car by hand every evening. Bemis's smart models (for example the Charger Pro 2 with a GSM connection and devices with OCPP 1.6 support) help you schedule the charge and manage scenarios that run it in the night period, so you do not miss the cheapest hours.
A step-by-step worked example (hypothetical)
In the example below we label the unit electricity price as A TL/kWh, entirely as a hypothetical value. When you put the current unit price from your own bill (preferably the night-period price) in place of A, you will see your real cost. Let us assume our car uses 18 kWh per 100 km.
- Step 1 — The car's consumption: 18 kWh/100 km (hypothetical, example car).
- Step 2 — Add the charging losses: 18 × 1.1 ≈ 19.8 kWh (the real energy drawn from the socket).
- Step 3 — Multiply by the unit price: 19.8 kWh × A TL = the cost for 100 km.
- Step 4 — Per kilometre: (19.8 × A) ÷ 100 = the cost per kilometre in TL/km.
As you can see, the only unknown is A, that is, your unit price. The moment you substitute A, both the cost for 100 km and the cost per kilometre become clear. With the low A value of the night tariff, this figure comes down markedly compared with the daytime.
| Car consumption (kWh/100 km) | Including charging losses (kWh/100 km) | Cost for 100 km | Cost per kilometre |
|---|---|---|---|
| 15 | 16.5 | 16.5 × A TL | 0.165 × A TL/km |
| 18 | 19.8 | 19.8 × A TL | 0.198 × A TL/km |
| 22 | 24.2 | 24.2 × A TL | 0.242 × A TL/km |
How do you compare with a petrol car?
To compare like with like, apply the same logic to the petrol car. The cost of a petrol car is also a single multiplication: you multiply the litres burned per 100 km by the price per litre. Say the petrol car burns 7 litres per 100 km and the price per litre is B TL (again hypothetical). Then the cost for 100 km is 7 × B TL, and the cost per kilometre is (7 × B) ÷ 100 = 0.07 × B TL/km.
- Petrol cost for 100 km = Fuel consumption (L/100 km) × Price per litre (B TL/L)
- Petrol cost per kilometre = (L/100 km ÷ 100) × B TL/L
- Comparison: put the electric cost per kilometre (0.198 × A) and the petrol cost per kilometre (0.07 × B) side by side with your own current A and B values.
When you substitute the unit electricity price from your own bill (A) and the current fuel price at the pump (B), you will see that the fuel cost per kilometre of an electric car charged at home on the night tariff generally comes out substantially lower than that of a petrol car. Since the numbers change over time, keeping the formula to hand lets you make the up-to-date comparison yourself in every period.
Practical ways to lower the cost of charging at home
- Switch to a multi-rate tariff and schedule charging for the night period.
- Track your car's real kWh/100 km consumption and avoid exaggerated estimates.
- Keep your budget realistic by allowing for the charging losses (~10%).
- Catch the cheapest hours automatically with a home charger that can be scheduled.
- Charge safely and efficiently by choosing a wallbox of a power suited to your home's distribution board.
Looking for a schedulable charging solution of the right power for your home? See the Bemis home wallbox models.
See the wallbox modelsFrequently Asked Questions
How much does charging an electric car at home cost per kilometre?
The cost per kilometre depends on two things: how many kWh your car uses per 100 km and the unit price of electricity. The formula is: (consumption in kWh/100 km ÷ 100) × unit price. For example, on a car that uses 18 kWh per 100 km, you add the 10% charging losses and calculate on 19.8 kWh. To see the result you need to substitute the current unit price from your bill. We do not give a firm figure in TL because electricity prices change over time; but the formula is always the same and lets you find your own figure in seconds.
How much does charging on the night tariff save?
In Türkiye's multi-rate tariff the day is divided into three periods, and the night period is markedly the cheapest. When you plug the car in during the evening and let the charge fall into the night hours, you buy the same energy at a lower unit price than in the daytime or peak period. The exact scale of the saving depends on the current price difference between the periods; you can see that difference on your bill. A schedulable charger helps you capture this advantage regularly by planning the charge into the night period automatically, without you having to keep track of the car by hand.
What are charging losses and how do they affect the cost?
The energy you draw from the socket is somewhat more than the energy that goes into your battery. The difference is lost as heat in the cable, the converter and the battery management. In home AC charging this loss is around 10%. So the real consumption that shows up on the bill is a little higher than the net energy the car uses. To calculate the cost correctly, multiply the car's kWh consumption by roughly 1.1 or add 10% to it. It looks small in a single session, but over a year of high mileage the total difference becomes noticeable, so it is worth allowing for it in your budget planning.
Is an electric car really cheaper than a petrol one?
To make the comparison correctly, calculate both cars with the same formula. For the electric one, the cost per kilometre is consumption multiplied by the unit electricity price; for the petrol one, it is litre consumption multiplied by the price per litre. When you substitute your own current electricity and fuel prices, you will see that the fuel cost per kilometre of an electric car — especially one charged at home on the night tariff — generally comes out substantially lower than that of a petrol car. The exact ratio varies with prices; that is why the soundest approach is to use the formula and make the comparison yourself with current figures.
How do I find out how many kWh my car uses per 100 km?
The most accurate value is on your car's own screen. On most electric cars the average consumption appears on the instrument panel as "kWh/100 km" and reflects your real driving habits. To give a general range, electric cars typically use between 15 and 22 kWh per 100 km; compact models sit near the lower end, while large vehicles and high-speed motorway driving are near the upper end. In winter, consumption rises because of heating. Using the real average shown by the car rather than an estimate gives the most accurate figure per kilometre in your cost calculation.
