EV Charging Cost Calculator
Estimate EV grid energy, charging time, session cost, monthly charging cost and added driving range from battery and charger inputs.
Default project preview
$9.00
Battery energy added
45 kWh
Grid energy
50 kWh
Charging time
4.55 hours
Estimated range added
158 mi
Calculator
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Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Usable battery capacity
Enter this project assumption in kWh. The current imperial default is 75 kWh.
Starting charge
Enter this project assumption in %. The current imperial default is 20 %. Minimum: 0. Maximum: 100.
Target charge
Enter this project assumption in %. The current imperial default is 80 %. Minimum: 0. Maximum: 100.
Delivered charger power
Enter this project assumption in kW. The current imperial default is 11 kW.
Charging efficiency
Enter this project assumption in %. The current imperial default is 90 %. Minimum: 1. Maximum: 100.
Electricity price
Enter this project assumption in per kWh. The current imperial default is 0.18 per kWh. Minimum: 0.
Charging sessions per month
Enter this project assumption in a unitless value. The current imperial default is 20. Minimum: 0.
Vehicle efficiency
Enter this project assumption in mi/kWh. The current imperial default is 3.5 mi/kWh.
How to read the outputs
Battery energy added
stored in battery. Default preview: 45 kWh.
Grid energy
90% efficiency. Default preview: 50 kWh.
Charging time
11 kW delivered power. Default preview: 4.55 hours.
Estimated range added
entered vehicle efficiency. Default preview: 158 mi.
Monthly grid energy
20 sessions. Default preview: 1,000 kWh.
Monthly charging cost
same session repeated. Default preview: $180.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Battery energy added = usable capacity × charge increase. Grid energy divides by charging efficiency. Time = grid energy ÷ charger power; cost = grid energy × electricity rate.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: August 19, 2026
Estimate battery energy added, grid energy drawn, charging time and electricity cost for a charge window using usable battery capacity, charger power and charging efficiency.
Calculation steps
- 1Calculate the battery percentage increase and multiply by usable battery capacity.
- 2Divide battery energy by charging efficiency to estimate grid energy.
- 3Divide grid energy by delivered charger power for idealized charging time.
- 4Multiply grid kWh by the applicable electricity tariff and sessions for monthly cost.
Worked numerical example
A 75 kWh usable battery charged from 20% to 80% gains 45 kWh. At 90% charging efficiency the grid supplies about 50 kWh. An 11 kW charger takes roughly 4.55 hours at full delivered power and costs 9.00 at an electricity rate of 0.18/kWh.
Purchasing and rounding
For EVSE selection, verify vehicle AC charging limit, circuit capacity, connector type, cable reach and listed equipment. A higher-rated charger does not make a vehicle accept more power.
Interpret the result
The session cost reflects energy drawn from the grid under the entered efficiency. Actual time can be longer because vehicles taper charging power and manage battery temperature.
Page-specific assumptions
- Usable battery capacity is known.
- Average charging efficiency represents the session.
- Charger power is continuously available for the estimate.
Common mistakes
- Using gross battery capacity instead of usable capacity.
- Ignoring vehicle charge-rate limits.
- Treating the simple time result as guaranteed end-to-end session duration.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
Related tools
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Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
EV Charging Cost Calculator questions
Why is grid energy greater than battery energy?+
Charging losses occur in conversion, wiring, battery conditioning and vehicle systems.
Why can actual charging take longer?+
The vehicle may limit power or taper charging as battery temperature and state of charge change.
Does this include public charging fees?+
Only when the entered per-kWh price represents the complete charging tariff.