What This Calculator Does
You just bought a Tesla Model 3 with a 79 kWh battery. Your residential electricity rate is 18.34 cents per kWh. How much does a full charge cost? The math: 79 x $0.1834 = $14.49. That charge gives you roughly 277 miles of range, so your cost per mile is about 5.2 cents. Compare that to a 30 MPG gas car at $4.15 per gallon, which costs 13.8 cents per mile. The EV is nearly three times cheaper to fuel. But the picture changes fast if you rely on public DC fast charging, where rates can hit 42 cents per kWh or more.
This calculator takes three core inputs: your EV battery size in kWh, your vehicle efficiency in miles per kWh, and your electricity rate per kWh. It returns the full charge cost, cost per mile, cost per 100 miles, partial charge cost between any two battery percentages, and an annual charging cost estimate based on your driving habits. You can also compare costs across home, off-peak, public Level 2, DC fast, and Tesla Supercharger pricing tiers.
According to the US Energy Information Administration, the average residential electricity rate was 18.34 cents per kWh as of June 2026, up 5.0% year over year. AAA reports the national average for public EV charging is 42.4 cents per kWh as of August 2026. That gap between home and public charging is the single biggest factor in EV running costs.
Inputs Required
- Battery Size: Total usable battery capacity in kWh (check your vehicle specs)
- EV Efficiency: Miles per kWh, typically 2.5 to 4.5 depending on vehicle and conditions
- Electricity Rate: Cost per kWh from your utility bill or the charging station rate
- Charge Range: Optional from and to battery percentages for partial charge costs
- Annual Miles: Your yearly driving distance for annual cost projection
Outputs Provided
- Full Charge Cost: Total cost to charge from 0% to 100%
- Partial Charge Cost: Cost to charge between two battery percentages with estimated miles added
- Cost per Mile and per 100 Miles: Useful for comparing against gas vehicles
- Annual Charging Cost: Projected yearly fueling cost based on your mileage
- Charging Type Comparison: Bar chart showing cost across home, public, and fast charging tiers
How the Calculation Works
The core formula is simple. Energy consumed multiplied by price per unit of energy equals cost.
Full Charge Cost = Battery Size (kWh) x Electricity Rate ($/kWh)
Cost per Mile = Electricity Rate / EV Efficiency (mi/kWh)
Annual Cost = Cost per Mile x Annual Miles
Partial Charge = Battery Size x (To% - From%) / 100 x Rate
The battery size tells you how much energy the vehicle can store. The efficiency tells you how far that energy takes you. The rate is what you pay per unit of energy. Multiplying battery size by rate gives the full charge cost. Dividing rate by efficiency gives cost per mile. For a partial charge, you calculate what fraction of the battery you are filling and multiply by the total capacity and rate.
For the Tesla Model 3 example: 79 kWh x $0.1834 = $14.49 for a full charge. At 3.5 miles per kWh, cost per mile is $0.1834 / 3.5 = $0.0524. Over 12,000 miles per year, that is $628.80 in electricity. The same 12,000 miles in a 30 MPG gas car at $4.15 per gallon would cost $1,660. The EV saves $1,031.20 per year on fuel alone. To see this comparison in detail, use our EV vs Gas Cost Calculator.
How to Use the Calculator
- Select an EV model preset or enter your battery size in kWh manually.
- Enter your EV efficiency in miles per kWh. Most EVs get 2.5 to 4.5 mi/kWh.
- Choose a charging type preset or enter your electricity rate manually. Check your utility bill for your exact rate.
- Optionally set a partial charge range (for example, 20% to 80%) to see the cost of a typical daily top-up.
- Enter your annual miles driven to see your projected yearly charging cost.
- Compare costs across charging types using the bar chart to see how much you save by charging at home.
Example Calculations
Example 1: Home Charging a Tesla Model Y
Maria in Austin drives a Tesla Model Y with an 81 kWh battery at 3.3 miles per kWh. Her residential electricity rate is 15.94 cents per kWh (the Texas average as of June 2026). A full charge costs 81 x $0.1594 = $12.91. Cost per mile is $0.1594 / 3.3 = $0.0483. Over 14,000 miles per year, her annual charging cost is $676.20. She charges overnight on a time-of-use plan that drops to 9 cents per kWh, which would cut her annual cost to $381.80, saving $294.40 per year.
Example 2: Public DC Fast Charging on a Road Trip
James is driving his Hyundai Ioniq 5 (84 kWh battery, 3.2 mi/kWh) from Los Angeles to Las Vegas, a 270-mile trip. He stops at an Electrify America DC fast charger charging 48 cents per kWh. He charges from 15% to 85%, adding 70% of 84 kWh = 58.8 kWh. Cost: 58.8 x $0.48 = $28.22. That adds about 188 miles of range. His cost per mile on this charge is $0.48 / 3.2 = $0.15, which is comparable to a 28 MPG gas car at $4.15 per gallon ($0.148 per mile). Public fast charging erases much of the EV cost advantage.
Real World Scenarios
The Off-Peak Home Charging Advantage
Derek in San Diego pays 32 cents per kWh on his standard plan but switches to a time-of-use rate that charges 12 cents per kWh between midnight and 6 AM. His Rivian R1T has a 135 kWh battery at 2.2 mi/kWh. At the standard rate, a full charge costs $43.20. At the off-peak rate, it costs $16.20. Over 15,000 miles per year, he uses 6,818 kWh. Standard rate: $2,181.76. Off-peak rate: $818.16. The TOU plan saves him $1,363.60 per year. Many utilities offer EV-specific time-of-use plans that make home charging even cheaper than the residential average.
Mixed Charging: Mostly Home, Occasional Road Trips
Priya drives 13,000 miles per year in her Chevy Bolt (66 kWh, 3.5 mi/kWh). She charges at home 90% of the time at 16 cents per kWh and uses DC fast charging 10% of the time at 42 cents per kWh. Home charging: 11,700 miles / 3.5 = 3,343 kWh x $0.16 = $534.88. Fast charging: 1,300 miles / 3.5 = 371 kWh x $0.42 = $155.82. Total annual cost: $690.70. If she charged exclusively at home, it would be $594.29. The 10% fast charging adds $96.41 per year, a modest premium for road trip convenience.
Comparing Two EVs With Different Efficiency
A Tesla Model 3 at 4.1 mi/kWh and a Ford F-150 Lightning at 2.0 mi/kWh both charge at home at 18 cents per kWh. Over 12,000 miles, the Model 3 uses 2,927 kWh costing $526.83. The Lightning uses 6,000 kWh costing $1,080.00. The truck costs $553.17 more per year to fuel, despite using the same electricity source. Efficiency matters as much for EVs as MPG does for gas cars. To compare your EV against a specific gas vehicle, try our EV vs Gas Cost Calculator.
Common Mistakes to Avoid
- Using the EPA efficiency rating as a guarantee: EPA ratings are measured under controlled conditions. Real-world efficiency drops 15 to 30% in cold weather due to battery heating and cabin heating. A Model 3 rated at 4.1 mi/kWh may deliver 3.1 mi/kWh in January in Minnesota.
- Forgetting charging losses: About 10 to 15% of the energy from your wall outlet is lost as heat during AC to DC conversion in the charger and battery. A 79 kWh battery may require 90 kWh from the wall to fully charge. This calculator does not account for charging losses.
- Ignoring demand charges at DC fast stations: Some DC fast chargers bill per minute rather than per kWh, and idle fees can add $0.40 to $1.00 per minute if you leave your car plugged in after charging completes. Check the network's pricing structure before you plug in.
- Using a single rate for mixed charging: If you charge 80% at home and 20% on the road, your effective rate is a weighted average. Using just the home rate understates your real cost. Using just the public rate overstates it. Calculate each segment separately for accuracy.
Limitations of This Calculator
This tool estimates charging cost from battery size, efficiency, and a single electricity rate. It does not account for charging losses (typically 10 to 15%), battery degradation over time, temperature effects on efficiency, or variable time-of-use pricing schedules. Public charging prices vary by network, location, time of day, and membership status, so the preset rates are national averages. For a full cost of ownership analysis including insurance, maintenance, and depreciation, consult a comprehensive EV cost tool. To estimate the carbon impact of your EV driving, pair this with our Carbon Footprint Calculator.
Authoritative Research and Resources
- EIA: Electric Power Monthly - The US Energy Information Administration publishes monthly average residential, commercial, and industrial electricity rates by state. The June 2026 national average residential rate is 18.34 cents per kWh.
- Fueleconomy.gov: EPA Fuel Economy Guide - Official EPA ratings for EV efficiency (kWh per 100 miles), MPGe, and range for every electric vehicle sold in the United States.
- DOE Alternative Fuels Data Center: Electricity Prices - The Department of Energy tracks electricity prices for EV charging and provides state-by-state charging cost comparisons.
For related tools, try our EV vs Gas Cost Calculator for a head-to-head fueling cost comparison, our Fuel Cost Calculator for gas vehicle trip costs, or our Carbon Footprint Calculator to estimate your driving emissions.