Last updated: 2026-06-22

EV Charging Cost

The cost of charging an electric vehicle at home or a public station is straightforward to estimate: multiply the energy drawn from the grid by the electricity rate. The key detail is that the grid must supply slightly more energy than the battery stores, because charging is not perfectly efficient.

The Formula

Where $C$ is battery capacity (kWh), $\text{SoC}_1 - \text{SoC}_0$ is the state-of-charge range, $\eta$ is charging efficiency, and $p$ is the electricity price per kWh.

Worked Example

A 75 kWh battery is charged from 10% to 80% at home. The charger runs at 90% efficiency and the electricity rate is 0.28 per kWh.

• Net energy to store: $75 \times (0.80 - 0.10) = 52.5\ \text{kWh}$
• Grid energy drawn: $52.5 \div 0.90 = 58.33\ \text{kWh}$
• Session cost: $58.33 \times 0.28 \approx 16.33$

What Drives the Cost

Electricity rate is the largest variable. Home residential rates are typically 0.10–0.35 per kWh depending on country and time of day. Public DC fast-charger networks usually price higher — often 0.35–0.70 per kWh, plus possible session fees — making home charging significantly cheaper for routine top-ups.

Charging efficiency affects how much grid energy a session consumes. Level 2 AC charging is typically 88–92% efficient. DC fast charging efficiency varies more with battery temperature and state of charge; below freezing or above 80% SoC, efficiency often falls.

SoC range determines how much energy moves. Charging from 20% to 80% on a 60 kWh pack moves 36 kWh net; the same range on a 100 kWh pack moves 60 kWh.

Time-of-Use Tariffs

Many utilities offer lower overnight rates. If your tariff charges 0.10 per kWh from midnight to 6 am rather than 0.28 during peak hours, the same session costs roughly 35% of the peak-rate price. Most EVs and home chargers support scheduled charging to take advantage of these windows.

Related Calculators

• EV Charging Time Calculator — estimate how long the same session will take
• Electricity Cost Calculator — calculate running costs for any electrical device
• Fuel Cost Calculator — compare EV charging costs with petrol or diesel