';detailText+='Energy added to battery: '+energyNeeded.toFixed(2)+' kWh
';detailText+='Energy pulled from grid (with '+ (eff*100) +'% efficiency): '+energyFromGrid.toFixed(2)+' kWh
';detailText+='Cost per kWh: $'+rate.toFixed(2);if(document.getElementById('steps').checked){document.getElementById('detailRes').innerHTML=detailText;document.getElementById('detailRes').style.display='block';}else{document.getElementById('detailRes').style.display='none';}}
Using the EV Charge Cost Calculator
Switching to an electric vehicle (EV) is a significant move toward sustainability and long-term savings. However, understanding exactly how much it costs to "fill up" can be confusing compared to traditional gas stations. This ev charge cost calculator is designed to provide clarity by estimating your charging expenses based on your specific vehicle and local utility rates.
Whether you are charging at home overnight or planning a stop at a public station, knowing your costs helps you budget effectively and maximize the value of your EV investment.
- Battery Capacity (kWh)
- The total energy your EV battery can hold, measured in kilowatt-hours (kWh). You can find this in your owner's manual or vehicle specs.
- Current and Target Charge (%)
- Input your starting battery percentage and how much you want to charge it. Most experts recommend a target of 80% for daily use to preserve battery health.
- Electricity Rate
- The price you pay per kWh. For home charging, check your utility bill. For public charging, check the app or station screen.
- Charger Efficiency
- Energy is lost as heat during the charging process. Standard home chargers are usually 85% to 90% efficient.
How Charging Costs are Calculated
The math behind the ev charge cost calculator is straightforward but requires accounting for energy loss. The electricity your car receives is slightly less than the electricity the grid provides because the onboard charger generates heat.
Cost = [ (Target % – Current %) / 100 × Capacity / Efficiency ] × Rate
- Energy Needed: The amount of kWh required to reach your target percentage.
- Efficiency Factor: Dividing by efficiency (e.g., 0.90) accounts for the extra power pulled from the wall that doesn't make it into the battery.
- Total Cost: The final bill based on your local utility price.
Calculation Example: Tesla Model 3
Scenario: You have a Tesla Model 3 with a 75 kWh battery. You arrive home with 20% charge and want to charge to 80% for the next morning. Your local electricity rate is $0.13 per kWh.
Step-by-step solution:
- Determine charge increase: 80% – 20% = 60%
- Calculate kWh added: 75 kWh × 0.60 = 45 kWh
- Adjust for 90% efficiency: 45 / 0.90 = 50 kWh (actual energy pulled from grid)
- Calculate cost: 50 kWh × $0.13 = $6.50
- Total Result: $6.50 to add roughly 160 miles of range.
Factors That Affect Your Charging Costs
Home vs. Public Charging
Home charging is almost always the cheapest way to fuel an EV. Residential rates typically range from $0.10 to $0.20 per kWh. Public DC Fast Charging (like Tesla Superchargers or Electrify America) often costs $0.30 to $0.50 per kWh because you are paying for the speed and infrastructure. Using an ev charge cost calculator can help you decide if a public charge is worth the premium.
Time-of-Use (TOU) Rates
Many utility companies offer "Time-of-Use" plans where electricity is much cheaper at night (off-peak). By scheduling your EV to charge after midnight, you could potentially cut your costs by 50% or more compared to charging during the evening peak hours.
Ambient Temperature
Batteries are less efficient in extreme cold or heat. In the winter, your car may use energy to warm the battery before charging begins, which lowers overall efficiency and slightly increases the cost per mile.
Common Questions
Is it cheaper to charge an EV than to buy gas?
In almost every scenario, yes. On average, driving an EV costs about one-third the price per mile compared to a gasoline vehicle. For example, $7 of electricity might take you as far as $25 of gasoline in a comparable sedan.
Does charging to 100% cost more?
The cost per kWh remains the same, but the final 10-20% of charging is much slower and can be less efficient due to heat management systems working harder to balance the cells. For daily driving, stopping at 80% is more time-efficient and cost-effective.
How much does it cost to charge at a Tesla Supercharger?
Supercharger prices vary by location and time of day. Generally, expect to pay between $0.25 and $0.50 per kWh. A full charge for a Long Range Model 3 might cost between $18 and $35 at a Supercharger, compared to about $9 at home.