How it works
Usable capacity is the battery energy available to the driver, which can differ from advertised total pack capacity. Enter starting and target percentages within 0–100. Target cannot be below the start. Charging efficiency describes battery energy gained divided by grid energy consumed, so a 90% example draws more energy from the wall than reaches the battery.
Match the unit price to the meter boundary in your tariff or charging receipt. Use grid input energy for a wall-metered home tariff. Select energy added to the battery only when that is actually the billed quantity. Public charger metering boundaries and included losses vary; the option is a modeling convention you must verify. Time uses average grid input power and is not a charging-curve prediction.
The formula behind the estimate
Every result starts with a defined model and visible assumptions.
Battery energy added = usable capacity × (target charge − starting charge) ÷ 100 Grid energy = battery energy added ÷ (charging efficiency ÷ 100) Billed energy = grid energy OR battery energy, using your selected tariff boundary Session cost = billed energy × unit price + flat session fee Time = grid energy ÷ average grid input power
A worked example
A hypothetical 60 kWh usable battery charged from 20% to 80% gains 36 kWh. At 90% charging efficiency, grid input is 40 kWh. At 0.20 per grid kWh with no session fee, the cost is 8.00 in the selected currency. At an average 7.2 kW input, the energy-based duration is about 5.56 hours. These are illustrative assumptions, not current electricity prices or a vehicle-specific charging test.
Home and public charging costs
The energy-price input accepts a local currency amount per kWh. A flat session fee is added once. It does not represent a monthly subscription or a per-minute charging price. Include applicable per-kWh taxes in the rate and any fixed transaction charge in the session fee. Time-of-use rates that change mid-session require separate calculations for the relevant portions.
Why kW and kWh are different
kWh measures energy; kW measures power, the rate of transferring energy. Dividing required grid energy by average grid input power estimates hours. A charger advertising a peak power does not deliver that peak throughout every session. Vehicle limits, charging taper, weather and equipment affect actual time. Efficiency is an assumption, not a guaranteed property of a charger.
Compare costs in one currency
Choose USD, PKR, INR, GBP, CAD, AUD, AED or EUR and enter prices in that currency. Changing the selection does not convert amounts or supply a national tariff. Source links describe US charging concepts, not rates for another country. The fuel-cost calculator covers petrol and diesel budgets; this session estimate does not claim a full EV-versus-gas ownership comparison.
Questions worth asking
Does this include charging losses?
Yes. Grid energy is battery energy divided by charging efficiency. Set the efficiency assumption for your session and tariff boundary.
Should I use advertised battery capacity?
Use usable capacity when available. Total pack capacity and usable capacity can differ, which changes the energy estimate.
Is the time result a guaranteed charging time?
No. It assumes your average grid input power stays as entered. Charging taper, temperature and equipment can change actual duration.
Are public charging fees included?
Only the entered unit price and one flat session fee. Subscriptions, idle charges, parking, per-minute billing and installation are excluded.
Does this find electricity prices in my country?
No. Currency selection controls display only. Enter the applicable local tariff and confirm how energy is metered.
This is general information, not personalized financial advice. Read the limitations.
