Before you choose a charger, a rate plan or FPL's EVolution Home program, it helps to know one number: how many kilowatt-hours your car will draw from the house each month. You do not need an app or a salesperson to work it out. You need three inputs, a calculator, and your electric bill. This post walks through the math with worked examples, then shows how to turn kWh into a cost using the rates printed on your own bill.
We are not quoting cents per kWh here, because rates change and differ by plan. The method stays the same. For the wider picture, see the Florida Home EV Charging Guide.
The three inputs
- Your car's consumption in kWh per 100 miles. This is on the EPA label and on fueleconomy.gov, which explains that the value "tells you how many kilowatt-hours the vehicle would use to travel 100 miles." Many 2026 sedans and crossovers on fueleconomy.gov fall roughly between 23 and 30 kWh per 100 miles. Trucks and large SUVs use more.
- Your miles driven. Per day, per week or per month. Your car's trip meter or your last few service records will tell you.
- Charging efficiency. Some energy is lost as heat between the wall and the battery. Fueleconomy.gov says battery charging efficiency "can vary, but it is often 84% to 93%, based on published studies."
The formula
Energy from the wall (kWh) = miles × (kWh per 100 miles ÷ 100) ÷ charging efficiency
If you take the consumption figure from your car's own display, which reports what the battery used on the road, dividing by the charging efficiency adds back the losses on the way in. The fueleconomy.gov label page does not say whether its kWh per 100 miles figure already includes those losses, so applying the efficiency step to the label figure gives you a cautious, upper-end estimate. For planning a circuit or a budget, cautious is fine.
Worked example: a 40-mile weekday
Take a crossover rated at 28 kWh per 100 miles, driven 40 miles a day.
- Battery energy for the day: 40 × 0.28 = 11.2 kWh.
- From the wall at 93% efficiency: 11.2 ÷ 0.93 = about 12.0 kWh.
- From the wall at 84% efficiency: 11.2 ÷ 0.84 = about 13.3 kWh.
- Over a 30-day month: roughly 360 to 400 kWh.
That range is your number. It is what you multiply by your rate, and it is what you compare against the plans in FPL's program.
Quick reference table
For a car rated at 28 kWh per 100 miles, with charging efficiency between 84% and 93%:
| Driving | Battery energy | From the wall per day | From the wall per 30 days |
|---|---|---|---|
| 20 miles a day | 5.6 kWh | 6.0 to 6.7 kWh | about 180 to 200 kWh |
| 40 miles a day | 11.2 kWh | 12.0 to 13.3 kWh | about 360 to 400 kWh |
| 60 miles a day | 16.8 kWh | 18.1 to 20.0 kWh | about 540 to 600 kWh |
| 15,000 miles a year | 4,200 kWh a year | about 4,520 to 5,000 kWh a year |
The 15,000-mile row matches the annual mileage fueleconomy.gov uses for the cost estimate on the EV label. If your car is rated differently, scale the figures: a car at 23 kWh per 100 miles uses about 18% less than the table, one at 35 kWh per 100 miles about 25% more.
The Florida summer adjustment
Heat costs range. In its May 2026 testing, AAA found that at 95 F compared with 75 F, EVs lost 10.4% efficiency and 8.5% range. For a July or August estimate, add roughly 10% to 12% to the kWh figures above. In the worked example, 360 to 400 kWh becomes roughly 400 to 450 kWh. Our post on Florida heat and EV charging covers the rest of the heat story.
From kWh to cost, using your own bill
Now multiply your monthly kWh by what you pay per kWh. Where to find that number depends on your plan:
- FPL standard residential (RS-1). Your bill and FPL's residential rates sheet list several per-kWh items: the base energy charge, the fuel charge, and smaller conservation, capacity, environmental and storm-related charges and credits. Add the per-kWh items together for your all-in rate. The energy and fuel charges are listed at one level up to 1,000 kWh a month and a higher level above it, so if your household already runs near 1,000 kWh in summer, use the higher figure for the EV's share.
- Whole-home time-of-use (RTR-1). Split your kWh into on-peak and off-peak and multiply each by its rate. If you schedule all charging off-peak, use the off-peak figures. Hours are in our post on FPL EV rates and off-peak charging.
- FPL EVolution Home. FPL's rates sheet lists two EV options, RS-1 EV and RS-2 EV, each with a monthly program charge. RS-1 EV adds a flat monthly off-peak energy charge plus a per-kWh on-peak charge; RS-2 EV prices both on-peak and off-peak energy per kWh. Add the monthly charges to your kWh times the per-kWh charges for the option you would be on. Our post on EVolution Home versus your own charger shows how to run that over the 10-year term.
- Homestead or Lake Worth Beach. Use your city utility's published rates: HPS Energy or Lake Worth Beach Electric Utilities.
Taxes and local charges on the bill come on top, so your real cost will be a little higher than the per-kWh arithmetic.
How long that takes to charge
Divide the energy by the charger's power. The Alternative Fuels Data Center puts Level 1 at about 1.9 kW and Level 2 typically at 7.2 kW. For the 40-mile day above, about 12.7 kWh from the wall:
- Level 1: 12.7 ÷ 1.9 = about 6.7 hours.
- Level 2 at 7.2 kW: 12.7 ÷ 7.2 = about 1.8 hours.
Your car's onboard charger may cap the rate below what the wall unit can supply, so check its maximum AC charging rate. Our post on how long it takes to charge an EV at home goes deeper, and Level 1 versus Level 2 covers when a standard outlet is enough.
Check your estimate against real data
After a month of driving, compare the estimate with measured numbers. Most EV apps log energy added per session, most Wi-Fi chargers report kWh delivered, and FPL's Energy Manager shows your household usage. If your measured figure is well above the estimate, look for heavy cabin cooling, lots of short trips, or a change in your driving since you made the estimate.
Questions homeowners ask
How many kWh does an EV use per month in South Florida?
It depends on the car and the miles. For a car rated at 28 kWh per 100 miles driven 40 miles a day, expect roughly 360 to 400 kWh a month from the wall, and more in the hottest months.
Where do I find my car's kWh per 100 miles?
On the EPA label or by searching your model on fueleconomy.gov.
Why divide by charging efficiency?
Because not all of the energy from the wall ends up in the battery. Dividing by 84% to 93% accounts for what is lost as heat along the way.
Will an EV push my FPL bill into the higher tier?
It can. FPL's rates sheet lists energy and fuel charges at one level up to 1,000 kWh a month and a higher level above it. Add your estimated EV kWh to your typical monthly usage to see where you land.
Does my panel need to be upgraded to supply this much energy?
Energy per month and power at any moment are different questions. The panel question is about amps while charging. See does my panel have room for an EV charger.
Once you know your monthly kWh, the right charger and circuit are easier to choose. KRW Electric (EC13012832) installs home chargers across Miami-Dade, Broward and Palm Beach and handles the permit and inspection. Tell us your car and your daily miles and we will size the circuit to match. More on the service: home EV charger installation.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
