Power Station Charging Cost Calculator
Estimate the cost of a full or partial battery recharge using your state’s EIA residential electricity rate—or enter your own utility rate.
Formula
Battery energy added = nominal watt-hours × the change in state of charge. Grid energy = battery energy added ÷ charging efficiency. Charging cost = grid kilowatt-hours × your electricity price per kilowatt-hour.
This means a 1,000Wh power station charged from 0% to 100% does not necessarily draw exactly 1.0kWh from the wall. At a 90% charging-efficiency assumption it draws about 1.11kWh. Using the current EIA U.S. year-to-date residential average of 18.16¢/kWh, that is roughly twenty cents.
Use your utility rate when you have it
The state presets use EIA year-to-date residential averages through June 2026. They are useful for comparison but are not the same thing as your marginal electricity price. If your bill shows a per-kWh energy charge, or you use a time-of-use tariff, replace the preset with the rate that actually applies when you charge.
Fixed monthly service charges normally should not be allocated to one battery recharge because you would pay them whether or not the power station was charged. Taxes and riders can be included if they change with energy consumption.
Why partial charges matter
Backup batteries are rarely cycled from exactly 0% to 100% every time. If you normally recharge from 30% to 80%, enter those values. The calculator uses only the 50 percentage-point change, producing a more realistic estimate of grid energy and cost.
What this calculator does not model
It does not estimate battery degradation, solar charging cost, demand charges, generator fuel, charging losses that vary by charge rate, or utility export credits. Those belong in separate ownership calculations. For long-term battery aging, use the cycle-life calculator; for battery-versus-generator economics, use the ownership-cost calculator.
State price source: U.S. EIA Electric Power Monthly Table 5.6.B, year-to-date through June 2026.