How Much Does It Cost to Charge an Electric Car?

The honest answer to "what does it cost to charge my EV" is a single line of arithmetic, but most people get it wrong by guessing from the number on the dashboard. The car tells you how much energy went into the battery. Your utility bills you for how much energy came out of the wall — and those two figures are not the same. Once you understand the gap, the cost per charge, the cost per mile, and the gap between home and public charging all fall out cleanly. Here is the math, with real numbers, and a tool that does it for you.

The core formula: kWh added times your rate

The cost of a charge is the energy you add multiplied by your price per kWh:

cost = kWh added × price per kWh

That is it for the simple case. If you add 30 kWh to the battery and you pay $0.15 per kWh, the charge cost you $4.50. The two inputs you need are your electricity rate (look at your bill — it is the per-kWh figure, sometimes split into off-peak and peak) and how much energy you are actually adding.

How much you add is your battery's usable capacity times the percentage window you charge. A 60 kWh battery charged from 20% to 80% adds 60 × 0.60 = 36 kWh. If you charge from empty to full on the same pack, that is the full 60 kWh.

Why you must add ~10% for charging losses

Here is the part the dashboard hides. Not all the energy your meter records reaches the battery. Some disappears as heat in the onboard charger, the cables, and the battery management system. On a home AC charger that loss is typically 8–12%; on a DC rapid charger it is lower, 3–6%, because the conversion happens in the charger rather than the car.

So the energy you pay for is higher than the energy that lands in the battery:

energy from the wall = battery energy ÷ (1 − loss)

For a 10% loss, 36 kWh into the battery means 36 ÷ 0.90 = 40 kWh pulled from the grid. Ignore this and you will consistently underestimate your bill by roughly a tenth. The EV charging cost calculator adds the loss on top automatically, so the figure it shows is what your utility actually charges, not the optimistic on-dash number.

A worked example: cost per charge and cost per mile

Let me run a clean example. Say you charge a full 60 kWh into the battery at a home rate of $0.15 per kWh, and we keep it simple by treating that as the energy delivered:

• 60 kWh × $0.15 = $9.00 for the charge.

Now turn that into a cost per mile. Suppose this charge takes you 240 miles of real-world driving. Then:

• $9.00 ÷ 240 miles = $0.0375 per mile, or about 3.75 cents a mile.

Add the 10% charging loss and the picture gets a touch more honest: 60 kWh into the battery is ~66.7 kWh from the wall, so the charge is closer to $10.00 and the cost per mile is about 4.2 cents. Either way you are in the 3 to 5 cents per mile range that defines home EV charging — and that is the number that makes electric cars cheap to run.

For drivers who think in metric, the same math gives cost per 100 km: take your consumption in kWh/100km, multiply by your rate, and gross up for loss. An EV at 17 kWh/100km on a $0.17 tariff costs about $2.89 per 100 km before losses.

Home versus public charging: the 2× to 4× gap

The single biggest swing in your running cost is where you plug in. Home charging is cheap. Public DC fast charging is a convenience tax, and the multiplier is large — typically 2× to 4× your home rate.

In the US a home rate of $0.17 sits against $0.40 to $0.60 at a DC fast charger. In the UK a home rate near £0.25/kWh sits against £0.79/kWh at a motorway rapid charger. Same battery, same kWh, two to four times the bill. The practical takeaway that nearly every owner lands on: charge at home overnight whenever you can, and treat public rapid charging as something you pay for on road trips, not as your default.

There is a small consolation on the loss side — DC charging is more efficient at the car (3–6% loss versus 8–12% at home) — but it never comes close to offsetting the higher per-kWh price. The toggle between home and fast-charge rates in the calculator puts both columns side by side so you can see the gap in dollars before you commit to a session.

Comparing to a gasoline car (do it per distance)

This is where the EV case usually wins, and it is also where people compare unfairly. Do not put "$9 to charge" next to "$60 to fill up" — those numbers are meaningless until you normalise by distance. The only fair comparison is per 100 km or per 100 miles.

Run both sides through the same distance. An EV at 17 kWh/100km on a $0.17 home tariff costs about $2.89 per 100 km. A petrol car at 8 L/100km with a $1.40/L pump price costs $11.20 per 100 km — roughly 4× more. Switch the EV to fast charging and that gap narrows; keep it on home charging and it widens. If you want to cross-check the fuel side independently, the fuel cost calculator handles the petrol math and MPG-to-L/100km conversions.

A word of warning on consumption: use a real-world figure, not the brochure. Official WLTP/EPA ratings assume mild weather and gentle speeds. Cold mornings and motorway cruising push real consumption well above the rated number, so if you want the honest cost, plug in your winter or highway figure rather than the best-case spec sheet value.

A note from my own driveway

I ran my own numbers before writing this, because I did not trust the round figures everyone quotes. My car shows about 18 kWh/100km on the trip computer in mild weather, but my charger's energy meter — the thing that actually counts what I pay for — reads closer to 20 once losses are added in. That 10% I almost forgot is the difference between a tidy estimate and the number that shows up on the bill. On my off-peak overnight rate the charging cost works out to a few cents a mile; on the rapid charger I used once on a long trip, it was nearly triple. Seeing both side by side is what convinced me to never let the battery dip low enough that I need a public charge mid-week.

Putting it together

The whole exercise comes down to three honest inputs: your real electricity rate, the kWh you actually add (grossed up for charging loss), and your real-world consumption. Get those right and the rest — cost per charge, cost per mile, the home-versus-public gap, the petrol comparison — is straightforward arithmetic. Start with the EV charging cost calculator, feed it your own tariff, and you will have a number that matches your bill instead of a number that matches a marketing slide.

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Made by Toolora · Updated 2026-06-13