Battery Charging Cost Calculator
This calculation estimates grid electricity needed to increase battery state of charge, then applies the user-entered tariff. Losses vary with equipment, temperature and charging power.
How to use this calculator
- Enter nominal battery capacity (kwh), starting charge (%), target charge (%), charging energy loss (%), electricity price per kwh using the same measurement window and units.
- Check the result and intermediate values, then change one input at a time when comparing scenarios.
- Keep the stated scope and assumptions attached to any result you share.
Formula and method
Stored energy = nominal capacity × SOC increase; grid energy = stored energy ÷ (1 − loss fraction); cost = grid energy × tariff.
- About 7.8 kWh is stored, 8.67 kWh is drawn from the grid and cost is about €2.69.
- Battery usable capacity may differ from nominal capacity, and fixed fees or time-of-use rates are not represented. Never exceed manufacturer charging limits.
Worked examples
Worked example
Charge a 12 kWh battery from 25% to 90%, with 10% losses and €0.31/kWh electricity.
About 7.8 kWh is stored, 8.67 kWh is drawn from the grid and cost is about €2.69.
About 7.8 kWh is stored, 8.67 kWh is drawn from the grid and cost is about €2.69.
Understanding the result
About 7.8 kWh is stored, 8.67 kWh is drawn from the grid and cost is about €2.69.
Battery usable capacity may differ from nominal capacity, and fixed fees or time-of-use rates are not represented. Never exceed manufacturer charging limits.
Important notes
Battery usable capacity may differ from nominal capacity, and fixed fees or time-of-use rates are not represented. Never exceed manufacturer charging limits.
Use measured inputs or documented assumptions, and validate important decisions with the appropriate source specifications or professional guidance.
Frequently asked questions
Should I use nominal or usable capacity?
Use usable capacity if the displayed SOC range maps to that capacity; avoid double-applying reserve limits.
Does this include a charger session fee?
No. Add any fixed session fee separately when comparing public charging providers.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.