The Cost Formula: Energy Needed x Electricity Price
Calculating the cost to charge an EV is straightforward: multiply the energy you need (in kWh) by the electricity price (in €/kWh or $/kWh). For example, if you need to add 40 kWh to your battery and pay €0.20/kWh, the charge costs €8.00. The energy needed depends on your starting and target state of charge (SOC) and the usable battery capacity.
How Much Does It Cost to Charge an EV?
There is one important nuance: charging is never 100% efficient. Some energy is lost as heat in the charger, cables, and battery management system. AC charging typically operates at around 90-92% efficiency, while DC fast charging achieves roughly 95%. This means you actually draw more energy from the grid than what ends up in your battery. A 40 kWh charge at 92% AC efficiency really draws about 43.5 kWh from the wall.
The Plan EV Charge calculator accounts for these efficiency losses automatically, giving you a more accurate cost estimate than simple back-of-the-envelope math.
Home Charging Costs vs Public Charging
Home charging is by far the cheapest way to charge an EV. Residential electricity rates in Europe typically range from €0.15 to €0.25/kWh depending on your country and tariff. In France, regulated tariffs sit around €0.18/kWh, while Germany averages closer to €0.30/kWh. In the US, the national average is roughly $0.13/kWh. Charging a 60 kWh battery from 20% to 80% at home costs between €5.40 and €9.00 in most European markets.
Public charging is significantly more expensive. AC destination chargers at supermarkets or parking garages typically charge €0.30-0.45/kWh. DC fast chargers from networks like Ionity, Fastned, or Tesla Superchargers range from €0.40 to €0.65/kWh, with some peak pricing exceeding €0.70/kWh. That same 20-80% charge on a 60 kWh battery could cost €14.40 to €23.40 at a public fast charger.
The takeaway is clear: if you can charge at home, you will save 50-70% compared to public charging. Even workplace charging, often free or subsidized, dramatically reduces your monthly charging budget.
Factors That Affect Your Charging Cost
Battery size is the most obvious factor. A Tesla Model 3 Standard Range with a 57.5 kWh battery costs less to fully charge than a Mercedes EQS with a 107.8 kWh pack, simply because it needs less energy. However, a larger battery also means more range per charge, so cost per kilometer may be similar.
The SOC range you charge matters too. Charging from 10% to 80% is more energy-efficient than charging from 80% to 100%. Above 80% SOC, the battery management system slows charging speed to protect battery health, and efficiency drops. On DC fast chargers especially, the last 20% can take as long as the first 60% and cost proportionally more in time-based billing scenarios.
Driving efficiency also plays a role. An EV rated at 15 kWh/100 km will cost roughly half as much to run as one consuming 25 kWh/100 km. Highway driving, cold weather, and heavy use of climate control all increase consumption and therefore charging frequency and cost.
Real Cost Examples for Popular EVs
Let's look at concrete numbers for a 20% to 80% charge (the most common charging window) at a home rate of €0.20/kWh and a DC fast charger rate of €0.50/kWh. The Tesla Model 3 Long Range (75 kWh battery) needs about 45 kWh for this charge: €9.78 at home or €24.46 at a DC charger, accounting for efficiency losses. The Hyundai Ioniq 5 (77.4 kWh) costs roughly €10.10 at home or €25.26 at DC.
Smaller EVs are even cheaper. The MG4 Standard (51 kWh) costs about €6.65 at home for a 20-80% charge. The Fiat 500e (42 kWh) needs only around €5.48 at home. On the other end, the BMW iX xDrive50 (105.2 kWh) costs approximately €13.73 at home or €34.32 at a fast charger for the same SOC range.
Per 100 km, most modern EVs cost between €3.00 and €5.00 when charged at home, compared to €8.00-€15.00 on public fast chargers. This is still significantly cheaper than petrol, where 100 km typically costs €8.00-€14.00 depending on the car and fuel prices.
Using the Calculator for Precise Cost Estimation
The Plan EV Charge calculator lets you simulate exact charging costs for your specific vehicle and situation. Select your car model, set your starting and target SOC, choose your charger type (or enter a custom power level), and input your local electricity rate. The calculator applies the correct efficiency losses and your car's actual DC charging curve to produce a realistic cost estimate.
This is especially useful for planning road trips. By simulating each charging stop with the charger power and price you expect, you can budget your trip costs in advance. The difference between a well-planned trip using affordable chargers and a haphazard approach can easily be €20-€40 on a 500 km journey.
You can also compare scenarios side by side. What if you charge to 90% instead of 80%? What if you use a 50 kW charger instead of 150 kW? The calculator shows you exactly how these choices affect both your time and your wallet, helping you find the sweet spot between convenience and cost.
