Hub · Charging Speed & Cost
“How fast does it charge?” is really three questions: how many amps the circuit delivers, how many kilowatts your car can accept, and how many miles of range that buys per hour plugged in. This hub does that translation — and the second translation that matters just as much: what each of those miles costs at your utility’s rate.
The conversion chain, worked
Amps times volts is watts. On a 240V circuit: 40 amps delivers 9.6 kW, 48 amps delivers 11.5 kW, and the 50-amp ceiling of the ChargePoint Home Flex delivers 12 kW. Kilowatts times your car’s efficiency is miles per hour — at a typical 3.2 miles per kWh, that’s roughly 31, 37, and 38 miles of range added per hour plugged in. Two honest caveats ride on every one of those numbers. Your car’s onboard charger is a ceiling of its own: plug an 11.5 kW circuit into a car that accepts 7.7 kW and you get 7.7 kW. And efficiency swings the answer more than amperage does — a pickup at 2.2 mi/kWh gains range about a third slower than a sedan at 3.8.
What 100 miles costs, three ways
Time-of-use plans: the real speed upgrade
A time-of-use plan doesn’t charge your car faster; it charges your wallet slower. Utilities commonly price overnight energy at half to two-thirds of the flat rate, and every charger in our flagship comparison can schedule around those windows. The trap is the other side of the plan: peak prices that punish a 6 p.m. kitchen. Run the plan against your household’s actual peak habits before enrolling — the savings live or die there, not at the charger.
What this hub covers
- Amps → kilowatts → miles per hour: the full conversion chain, worked for the circuits real homes have — 40A, 50A, and 60A.
- Your car is the ceiling: onboard charger limits (7.7 kW, 9.6 kW, 11.5 kW) and why a bigger circuit sometimes buys you nothing.
- Cost per mile, honestly: home vs. public Level 2 vs. DC fast charging vs. gasoline, modeled on EIA rates — and the efficiency figure (kWh per mile) that moves the answer most.
- Time-of-use plans: when overnight rates cut your cost per mile in half, and when the plan’s peak price makes it a trap.
The overnight test: if your car is home and plugged in for 8+ hours, even a 40A circuit adds roughly 250 miles overnight — more than almost anyone drives in a day. Speed stops mattering long before the biggest circuit does. The Electrical Setup hub covers what each circuit takes to install.
Best Home EV Chargers
Output translated into miles per hour and five-year cost for the five chargers that matter — see what the extra amps actually buy.
Electrical Readiness Checker
Speed costs circuit. Find out which circuit your panel can feed before you pay for amps you can’t use.
Charger-by-charger speed claims are checked against spec sheets in the Buying Guides; the boxes themselves live in Home Chargers.