How to calculate EV charging cost per kWh.

The basic formula

Charging cost = energy added (kWh) × electricity rate per kWh. For example, 42 kWh at $0.18 per kWh costs $7.56 before taxes or other fees. Use the amount billed by the charger when it differs from the vehicle's dashboard estimate.

Include every fee

Public networks may bill by energy, session, charging time, parking time, or subscription. Record each fee in the session total so cost-per-kWh comparisons reflect the amount actually paid.

Calculate effective cost per kWh

Effective cost per kWh = total session cost ÷ delivered kWh. A $12.60 session delivering 42 kWh has an effective cost of $0.30 per kWh. Keep the original currency and rate context when comparing sessions.

Estimate cost per distance

Multiply the vehicle's energy use per distance by the effective electricity rate. If an EV uses 18 kWh per 100 km and charging averages $0.20 per kWh, estimated energy cost is $3.60 per 100 km. Real results vary with weather, speed, charging losses, and driving conditions.

What to record

Save the date, vehicle, provider, location, AC or DC charging type, delivered kWh, and final amount paid. Consistent inputs make monthly totals and provider comparisons more useful.

Sources

• U.S. Department of Energy — Charging Electric Vehicles at Home
• U.S. Department of Energy — EV charging fees and pricing structures