EV Charging Cost Calculator
The Meter Reads More Energy Than the Battery Gains
Charging an EV isn't perfectly efficient — some energy is lost as heat in the charging cable, the onboard charger, and the battery management system before it ever reaches usable capacity. That means the electricity you're billed for is consistently more than the kWh your battery display shows gained, and any charging cost estimate that skips this step will undercount the real bill. This calculator accounts for charger efficiency explicitly, so the cost reflects what actually leaves the wall meter.
The Formula
Energy From Wall = Energy Needed ÷ Charger Efficiency
Cost = Energy From Wall × Electricity Rate
Charger efficiency defaults to 90% if left blank, a commonly cited figure for Level 2 home charging; DC fast charging and older Level 1 setups can differ.
Where This Matters
- Comparing home vs. public charging — home electricity rates and public charging network rates can differ by several multiples, and this calculator makes the true cost of each visible before you plug in.
- Budgeting a road trip — estimating the cost to charge from a low state of charge back to near-full at each stop helps plan a trip's total energy budget.
- Evaluating time-of-use electricity rates — many utilities charge different rates by time of day; running the same charging session at an off-peak vs. peak rate shows the potential savings of scheduled charging.
- Comparing to gasoline cost per mile — pairing this cost with the EV Range Calculator gives a cost-per-mile figure directly comparable to a gasoline vehicle's fuel cost.
Charging Cost, 75 kWh Battery, 20% to 100%
| Electricity Rate | Charging Cost |
|---|---|
| $0.12/kWh | $8.00 |
| $0.16/kWh | $10.67 |
| $0.20/kWh | $13.33 |
| $0.28/kWh | $18.67 |
| $0.35/kWh | $23.33 |
Computed directly from the calculator's formula at a fixed 75 kWh battery, 20%–100% charge, and 90% charger efficiency.
How to Use This Calculator
- Enter the battery's total capacity in kWh.
- Enter the starting charge percentage and target charge percentage.
- Enter the electricity rate in dollars per kWh.
- Enter charger efficiency if known (defaults to 90%).
- Optionally enter charger power in kW to also see an estimated charging time.
- Select Calculate to see energy drawn from the wall and total cost.
Related Calculations
Pair this with the EV Range Calculator to see how far that energy will actually take you.