MundoKit

EV charging cost calculator

Enter usable battery size, charge levels and your charging rates. Compare home and public session costs with an approximate charging time.

Inputs
kWh
%
%
kW
Use the lower of charger power and vehicle acceptance.
%
Fraction of supplied energy lost; change for your charging setup.
USD/kWh
USD per selected unit
USD
mi/kWh
%

Results

Home session cost
$8.00
Public session cost
$20.00
Energy added to battery
36 kWh
Supplied energy
40 kWh
Estimated charge time
5.56 hours
Home cost per 100 miles
$5.56
Public cost per 100 miles (session fee included)
$13.89
  • Rates are illustrative USD inputs. Taxes, idle fees and billing increments are excluded. Public kWh billing uses supplied energy; check the meter basis on your receipt.
  • Driving efficiency is battery-side mi/kWh. Do not add losses again to an efficiency figure that already includes charging losses.
  • DC time uses your retained-power assumption above 80%; temperature and the actual vehicle curve can change it substantially.

Results update as you type. The share link stores your inputs after the # in the address, which is not sent to our server, but anyone you send it to can read them.

How it works

Stored energy = usable battery kWh × (target − start) ÷ 100. Supplied energy = stored energy ÷ (1 − losses ÷ 100). The DOE/EPA combined-driving diagram estimates 10% charging losses; this is an editable starting assumption.

Home cost = supplied kWh × home rate Public cost = supplied kWh × public kWh rate + session fee Or public cost = estimated minutes × minute rate + session fee

AC time is supplied kWh ÷ available kW. EPA explains that DC charging slows around 80%. Our simple DC estimate uses full entered power below 80% and your chosen retained fraction above 80%. The default 50% retained power is an illustrative model assumption, not a verified vehicle curve. Set power to the lower of the charger and vehicle capability.

Cost per 100 miles divides session cost by battery energy added × battery-side mi/kWh, then multiplies by 100. With no range added, public cost per distance is undefined. No intermediate rounding is used; money displays cents, energy and hours up to two decimals. Per-minute billing uses exact estimated time, without provider-specific rounding.

Worked examples

Home charging

A 60 kWh battery from 20% to 80% adds 36 kWh. At 10% losses it draws 40 kWh. At $0.20/kWh the cost is $8.00, or $5.56 per 100 miles at 4 mi/kWh. At 7.2 kW it takes about 5.56 hours.

Public minute billing

A 60 kWh battery from 80% to 100%, at 10% losses and 60 kW, with DC power retained at 50%, takes 26.67 minutes. At $0.50/minute plus a $2 fee, cost is $15.33.

Frequently asked questions

Does 10% loss mean multiplying energy by 1.1?
No. If 90% of supplied energy reaches the battery, divide battery energy by 0.9. Adding 36 kWh therefore needs 40 kWh.
Why does fast charging slow near full?
EPA explains that the DC charge rate falls as the battery fills. Charging beyond about 80% can add substantial time; this calculator uses an adjustable simplified model.
Which electricity rate should I enter?
Use your actual marginal electricity price, including applicable energy taxes. Public chargers may bill by energy or time and may add session or idle fees.
Can I use EPA efficiency directly?
Use battery-side mi/kWh here. If your efficiency already counts grid charging losses, applying losses again would double count them.

Sources

Last reviewed 2026-11-14; next review due by 2026-12-14. The method is written out above so you can check our math.