How is the cost per 100 km or 100 miles calculated?

The yearly cost is divided by the distance you entered and multiplied by 100, so it stays comparable no matter how much you drive.

What charging loss should I use?

Home AC charging typically loses somewhere around 5-10% between the socket and the battery, and fast DC charging is usually lower. If your charger reports both figures, use your own.

Yes. Switch the unit and enter consumption as kWh per 100 miles; every field, result, and label follows the unit you picked.

Does it include a charging subscription?

No. It prices energy at the two rates you enter. If a subscription changes your public price, enter the price the subscription gives you and account for the monthly fee separately.

Why is my real cost higher than the result?

Cold weather, motorway speed, roof boxes, and a lower home share all push it up. Re-run it with your winter consumption to see the range rather than one number.

Can I share the calculation?

Yes. Share copies a link that reopens the calculator with the same distance, consumption, split, and prices.

EV charging cost calculator

Enter how far you drive in a year, what the car uses per 100 km or per 100 miles, how much of your charging happens at home, and the price you pay in each place. The calculator adds the charging loss on top, prices the energy you actually buy, and shows the cost per year, per month, and per 100 units of distance.

Written by Kenneth Schrøder, Founder of WiseCalcs

Updated September 6, 2026·Sources verified September 6, 2026

Charging cost comes down to three things: how far you drive, what the car uses, and how much of that energy you buy at a home rate rather than a public one — this calculator combines all three and shows the price per 100 km or 100 miles.

Charging cost per year

$916

Includes charging loss

Home: $563.48Public: $352.17

Cost per 100 mi: $7.63
Per month: $76
Energy bought per year: 3,913 kWh
Home charging: $563
Public charging: $352
Average price per kWh: $0.23

Cost per 100 mi by home share

Left: everything charged publicly. Right: everything charged at home.

The headline is what a year of charging costs at the prices you entered. The bar underneath splits it into home and public charging, and the small chart shows how the cost per 100 changes as more of your charging moves home.

How does it work?

The loss is applied to the grid side, so grid energy is battery energy divided by (1 − loss), not multiplied by it. Prices are the ones you enter; nothing is looked up. Subscription fees, parking, idle fees, and the cost of installing a home charger are not included.

EV charging cost formula

C = \frac{d}{100}\times\frac{e}{1-\ell}\times\big(s\,p_{h} + (1-s)\,p_{p}\big)

d: Distance driven per year, in km or miles.
e: Consumption in kWh per 100 km or per 100 miles.
ℓ: Charging loss as a share of grid energy.
s: Share of charging done at home.
p_h: Home price per kWh.
p_p: Public price per kWh.
C: Charging cost per year.

Driving 15,000 km at 18 kWh/100 km puts 2,700 kWh into the battery. With 8% charging loss the meter shows 2,935 kWh. Charging 80% at home at 0.30 and 20% away at 0.60 costs 705 + 352 = 1,057 a year — about 7.04 per 100 km, or a blended 0.36 per kWh.

Expert tips

Real consumption rises in cold weather and at motorway speed, so a winter figure and a summer figure can differ by a quarter or more.
Public charging is rarely one price. If you use several networks, enter a weighted average or run the calculation once per network.
A tariff with cheap night hours is not modelled separately; enter the average price you actually pay at home.

Method & sources

Distance times consumption gives the energy the car uses in a year. That figure is divided by the charging efficiency to get the energy you actually buy, split by the share you charge at home, and priced at the two rates you enter. Dividing the yearly cost back by distance gives a cost per 100 km or per 100 miles that you can compare with a petrol or diesel car.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

Regulation (EU) 2023/1804 on alternative fuels infrastructure — Publications Office of the European Union (EUR-Lex), verified 2026-09-06
Charging electric vehicles at home — U.S. Department of Energy, Alternative Fuels Data Center, verified 2026-09-06

How we calculate

Consumption is entered on the same basis as distance: kWh per 100 km with kilometres, kWh per 100 miles with miles.
Charging loss is applied to the energy you buy, so grid energy is battery energy divided by (1 − loss).
The home and public prices you enter are the all-in rates per kWh, including per-kWh taxes and fees.
The home/public split is the share of energy, not the share of charging sessions.
Only energy is counted. Subscription fees, parking, idle fees, roaming surcharges, and installing a home charger are outside the calculation.

Limitations

Real consumption rises in cold weather and at motorway speed, so a winter figure and a summer figure can differ by a quarter or more.
Public charging is rarely one price. If you use several networks, enter a weighted average or run the calculation once per network.
A tariff with cheap night hours is not modelled separately; enter the average price you actually pay at home.

Rounding

Yearly and monthly costs are rounded to whole units; cost per 100 and the average price per kWh keep two decimals, and energy is shown as whole kWh. The calculation uses full precision.

What this calculator does

An electric car has no single fuel price. The same car can cost three times as much per mile on a fast charger as it does on a home tariff overnight, so the useful question is not what electricity costs but what your mix costs. This calculator takes your distance, your consumption, your split between home and public charging, and the two prices, and turns them into one yearly figure and one cost per 100 units of distance.

How to use it

Pick kilometres or miles. Every field and result follows the unit you choose.
Enter your distance for a year and the car's consumption per 100 km or 100 miles.
Drag the slider to the share of energy you charge at home.
Enter the price per kWh you pay at home and the price you pay at public chargers.
Adjust the charging loss if you know yours; 5-10% is typical for home charging.

Why charging loss belongs in the calculation

The energy the meter bills you for is always more than the energy that reaches the battery. Some is lost as heat in the cable, the charger, and the battery itself, and some goes to conditioning the battery before it will take a charge. Because the loss sits between the socket and the battery, it is applied by dividing rather than multiplying: 2,700 kWh into the battery at an 8% loss means buying about 2,935 kWh.

A worked example

Take 15,000 km a year at 18 kWh per 100 km. That is 2,700 kWh into the battery, or 2,935 kWh bought with an 8% charging loss. Charging 80% at home at 0.30 per kWh costs 705, and the remaining 20% away at 0.60 per kWh costs 352. The year comes to 1,057 — about 7.04 per 100 km, and an average of 0.36 per kWh across the whole mix.

Where the numbers come from

Consumption is best taken from your own trip computer over several thousand kilometres rather than from the rated figure, which is measured under test conditions. The home price is the all-in rate per kWh on your electricity bill. For public charging, look at the price on the charging app for the networks you actually use, and take a weighted average if you switch between them.

Comparing with a petrol or diesel car

The cost per 100 km or per 100 miles is the figure to compare, because it is independent of how much you drive. Work out the same figure for a combustion car from its consumption and the fuel price, and put the two side by side. Charging almost entirely at home usually wins by a wide margin; charging almost entirely in public narrows the gap and can close it.

Common mistakes

Mixing units: kilometres with a kWh per 100 miles figure, or the other way round.
Using the battery capacity instead of consumption. A 60 kWh battery is not 60 kWh per 100 km.
Entering the share of charging sessions rather than the share of energy. Fast-charging sessions are usually bigger.
Forgetting that a public price often includes a per-minute or idle fee that is not part of the price per kWh.

What it does not cover

This is an energy calculation. A monthly subscription that lowers the public price per kWh, the cost of installing a home charger, and parking charges at the chargepoint all change the real total, and they are not in this result. Add them separately when you compare charging plans.

FAQ

How is the cost per 100 km or 100 miles calculated?: The yearly cost is divided by the distance you entered and multiplied by 100, so it stays comparable no matter how much you drive.
What charging loss should I use?: Home AC charging typically loses somewhere around 5-10% between the socket and the battery, and fast DC charging is usually lower. If your charger reports both figures, use your own.
Can I use miles?: Yes. Switch the unit and enter consumption as kWh per 100 miles; every field, result, and label follows the unit you picked.
Does it include a charging subscription?: No. It prices energy at the two rates you enter. If a subscription changes your public price, enter the price the subscription gives you and account for the monthly fee separately.
Why is my real cost higher than the result?: Cold weather, motorway speed, roof boxes, and a lower home share all push it up. Re-run it with your winter consumption to see the range rather than one number.
Can I share the calculation?: Yes. Share copies a link that reopens the calculator with the same distance, consumption, split, and prices.