Charging at home costs about $0.17 per kWh. Public DC fast-charging costs roughly $0.48 per kWh — often 2 to 3 times more. That gap is the single most important number in EV running costs. Two people can drive the same car the same miles, and the one who charges mostly at home can pay a fraction of what the other pays. The car is the same. The electricity price isn't.
So before you compare an EV to gas at all, you have to answer one question: where will you actually plug in? The answer changes everything downstream — your cost per mile, your monthly bill, and how quickly the EV pays off versus filling up at the pump.
Why home is so much cheaper
Home electricity is billed at your residential rate, which averages around $0.17/kWh across the US (yours may be higher or lower — check a recent bill). You charge overnight, slowly, and there's no markup for the charging hardware or the real estate it sits on.
Public DC fast-charging is a different product. You're paying for high-power equipment, a commercial site, grid demand charges, and a company that wants a margin. At roughly $0.48/kWh, that convenience is real, but it's priced like convenience. The point of fast-charging is speed on a trip, not saving money — and that's fine, as long as you know which one you're buying.
To put it in per-mile terms: an EV's cost per mile is the price per kWh divided by its efficiency in mi/kWh. A car that does 3.5 mi/kWh costs about $0.05/mile on home power ($0.17 ÷ 3.5) but about $0.14/mile on public fast-charging ($0.48 ÷ 3.5). Same car, nearly triple the cost, decided entirely by where you plugged in. We walk through this math in detail in the guide to EV charging cost per mile.
Blended cost: the number that actually matters
Almost nobody charges 100% at home or 100% in public. Your real cost is a blend — a weighted average based on the share of your kWh from each source.
The formula is simple. If h is the fraction of charging you do at home, your blended rate is:
- Blended $/kWh = (h × $0.17) + ((1 − h) × $0.48)
Run a few cases so the lever is obvious:
- 100% home: about $0.17/kWh — the best case, roughly $0.05/mile at 3.5 mi/kWh.
- 80% home / 20% public: about $0.23/kWh — still cheap, roughly $0.07/mile.
- 50/50: about $0.33/kWh — noticeably pricier, roughly $0.09/mile.
- 100% public: about $0.48/kWh — roughly $0.14/mile, which can rival or beat the pump on a per-mile basis.
Notice how fast the savings erode as the public share climbs. Every ten points you shift from home to public adds real money over a year. For a typical driver going ~12,000 miles, that difference adds up. Home charging isn't just a lever — it's the lever.
How to estimate your real mix
You don't need an app or a spreadsheet to get a usable estimate. Think about your week honestly:
- Do you have a place to plug in overnight? A garage, driveway, or even a standard 120V outlet you can reach. If yes, most of your daily miles can come from home power.
- How predictable is your driving? Commuting and errands are easy to cover at home. Frequent long, unplanned trips push you toward public charging.
- What's your building situation? No home outlet — apartment, street parking — means you'll lean heavily on public charging, and your blended rate climbs toward that $0.48 figure.
A practical rule of thumb: someone with reliable overnight charging and a normal commute often lands around 80–90% home. Someone without home access might be closer to 20–40% home. Pick the bracket that sounds like your life, plug the home share into the blend formula above, and you'll have a number far closer to reality than any generic average. If you're weighing the cost of adding a home charger to raise that share, WattDollar's home EV charger cost breakdown is a useful next stop.
The road-trip reality check
Long road trips are where public fast-charging is unavoidable, and that's okay. On a road trip you're paying that ~$0.48/kWh, so those miles cost more — sometimes close to what gas would cost per mile. The mistake isn't using fast-chargers on a trip; it's assuming your whole year looks like a road trip.
For most drivers, road trips are a small slice of annual mileage. If 90% of your year is home-charged commuting and 10% is fast-charged travel, your blended cost stays low. Just don't quote yourself the road-trip rate as your everyday rate — that's the error that makes people think EVs aren't cheaper when, charged mostly at home, they usually are. For the full picture on what a charge actually costs, see our guide on how much it costs to charge an EV.
Put your own numbers in
The averages here are a starting point, not your answer. Your electricity rate, your car's mi/kWh, and above all your home-vs-public split decide whether an EV saves you real money against the pump. Drop your own figures — including your home charging share and a look at live gas prices — into the gas-vs-EV calculator and see the break-even for your actual driving, not a national average.