Electric Car Charging Calculator

Introduction

This Electric Car Charging Calculator tells you how long it takes to charge your EV, what it will cost, and how much range you gain. Pick your car from the list or type in your own battery size and charging speed. You get your results.

The tool works for both AC charging (Level 1 and Level 2 at home) and DC fast charging at public stations. You can set your outlet voltage and amps, your start and target charge level, your power price, and even the weather. Cold and hot batteries charge slower, and the math here shows that.

You also see your charging cost next to the cost of gas for the same miles, plus the CO₂ you skip. Every step of the math is shown, so you can check the numbers yourself. Switch between miles and kilometers any time.

How to use our Electric Car Charging Calculator

Enter your car's battery size, your charger details, and how full you want the battery. The calculator shows your charging time, cost, energy used, range added, and how it compares to gas.

Distance Units: Pick miles or kilometers. All results switch to that unit.

Charging Type: Choose AC Charging for home Level 1 or Level 2 plugs. Choose DC Fast Charging for public fast chargers.

Search Vehicle: Type your make or model, like "Tesla Model 3." This fills in the specs for you. You can skip it and type your own numbers.

Usable Battery Capacity: Enter the kWh your battery can really use. Check your owner's manual if you are not sure.

Real-World Range: Enter how far your car goes on a full charge. Use your true driving range, not the sticker number.

Vehicle Max AC Rate: Enter the top kW your onboard charger accepts. Most cars are 6.6 to 11.5 kW.

Vehicle Max DC Rate: Shown only for DC fast charging. Enter the top kW your car can take from a fast charger.

Outlet / EVSE Preset: Pick the plug you use at home, like NEMA 14-50. Choose Custom to set your own volts and amps.

Voltage: Enter your supply voltage. Use 120V for a wall outlet, 240V for a Level 2 circuit, or 230V in Europe.

Amperage: Enter the amps your charger pulls. This should already be 80% of your breaker size.

Effective Outlet Output: This box fills in on its own. It shows the kW your outlet can deliver.

Station Preset: For DC charging, pick the station type, like CCS 150 kW or a Tesla Supercharger.

Station Output Power: Enter the station's kW if it is not in the list.

Starting Charge: Enter the battery percent you are plugging in at.

Target Charge: Enter the percent you want to reach. You can also drag the slider to set both numbers.

Electricity Rate: Enter what you pay per kWh. Your power bill shows this. The US average is about $0.17.

Charger Efficiency: Enter how much power reaches the battery. Level 2 home chargers are usually 85% to 95%.

Battery Temperature: Pick Cold, Normal, or Hot. Cold and hot weather slow charging down.

Charging Start Time: Set the time you plug in. The tool then tells you when your car will be ready.

Gasoline Price: Enter the price per gallon or per liter to compare fuel costs.

Comparable Gas Car Economy: Enter the MPG, L/100 km, or km/L of a similar gas car. Our Fuel Consumption Calculator converts between those units.

Click Calculate to see your results, steps, segment table, and charge chart. Click Reset to start over.

Electric Car Charging: What You Need to Know

Charging an electric car (EV) is like filling a gas tank, but with electricity. Your battery size is measured in kilowatt-hours (kWh). The speed of your charger is measured in kilowatts (kW). Divide the energy you need by the power you get, and you know how long the charge will take.

The Three Charging Levels

Level 1 (120V AC): A normal wall plug. About 1.2–1.9 kW. Adds roughly 3–5 miles of range per hour. Best for plug-in hybrids or short daily drives.
Level 2 (240V AC): A dryer-style outlet or home wall box. About 7–19 kW. Adds roughly 20–40 miles per hour. This is what most people install at home.
DC Fast Charging (Level 3): Public stations from 50 kW to 350 kW. Can go from 20% to 80% in 20–40 minutes. Used on road trips, not every day.

Why Your Car Sets the Real Speed

A charger can only give what your car will take. Every EV has an onboard charger that limits AC charging, often 7.2 kW, 11 kW, or 11.5 kW. If you plug an 11 kW car into a 19 kW box, you still charge at 11 kW. DC fast charging skips the onboard charger and feeds the battery directly, so the car's DC limit is what matters there.

Why Charging Slows Down Near Full

DC fast charging tapers. The battery takes full power up to about 80%, then slows a lot to protect the cells. Going from 80% to 100% can take as long as going from 20% to 80%. That is why road trip drivers stop at 80% and drive on. AC charging at home does not taper much, so the rate stays flat all the way to 100%.

Losses, Heat, and Cold

Not all the power from the wall reaches the battery. Some is lost as heat in the cable and charger. Home AC charging is usually 85–95% efficient, so you pay for a bit more energy than the battery gains. Long cable runs add their own losses, which our Voltage Drop Calculator quantifies. Cold weather is the bigger hit: below freezing, charging can be 30% slower because the car must warm the pack first. Very hot weather slows it too, around 15%.

What It Costs

Home charging cost is simple: grid energy used × your electricity rate. The US average rate is about $0.17 per kWh, so a full 60 kWh charge runs near $11. That is far less than gas for the same miles. Public DC fast chargers charge more, often $0.35–$0.60 per kWh, since you pay for speed.

Charging With Solar

If you have rooftop solar, daytime charging is the cheapest way to fuel a car. A 6 kW solar system in a sunny place makes about 25–30 kWh on a good day, which is enough for 80–100 miles of driving. Charging while the sun is up uses your own power instead of selling it back at a low rate. If your utility uses time-of-use rates, set your car to charge late at night or midday when power is cheapest. Solar plus a home battery lets you charge clean even after sunset.

Simple Tips

Charge to 80% for daily driving. Save 100% for long trips.
Plug in at home overnight; you wake up full almost every day.
Precondition the battery in winter while still plugged in.
Install a 240V circuit sized so the charger draws no more than 80% of the breaker rating, as the electrical code requires.

Formulas used

Effective AC outlet power

P_{outlet} = \frac{V \times A}{1000}

Peak charging power (charger vs. vehicle limit, temperature adjusted)

P_{peak} = \min(P_{charger},\ P_{vehicle}) \times k_{temp}

Energy delivered to the battery

E_{batt} = C \times \frac{SOC_{target} - SOC_{start}}{100}

Segment charging time with taper and charger efficiency

t_{seg} = \frac{E_{seg}}{P_{peak} \times m_{taper} \times \frac{\eta}{100}}, \quad m_{taper} = \{1.00,\ 0.70,\ 0.40\}

Grid energy drawn after charger losses

E_{grid} = \frac{E_{batt}}{\eta / 100}

Charging cost

\text{Cost} = E_{grid} \times r_{kWh}

Range added, average power and charging rate

\Delta R = \frac{SOC_{target} - SOC_{start}}{100} \times R_{max}, \quad P_{avg} = \frac{E_{batt}}{t_{total}}, \quad v_{charge} = \frac{\Delta R}{t_{total}}

Gasoline cost comparison and CO2 avoided

\text{Cost}_{gas} = \frac{\Delta R}{MPG} \times P_{gal}, \quad \Delta CO_2 = \left(\frac{\Delta R}{MPG} \times 8.887\right) - \left(E_{grid} \times 0.386\right)

Frequently asked questions

Why is my charging time longer than the simple math I did?

The tool adds charger loss to the time. If your charger is 92% efficient, only 92% of the power reaches the battery, so the pack fills slower. It also lowers power for cold or hot batteries and, on DC, slows the rate above 80%.

What is usable battery capacity and where do I find it?

Usable capacity is the part of the pack you can actually charge and drive with. Carmakers hold back a buffer to protect the cells.

Check your owner's manual or the window sticker.
A 77 kWh total pack may have about 75 kWh usable.
If you only know the total, subtract about 3–5%.

Should I enter my breaker size in the amperage box?

No. Enter the amps your charger actually pulls, not the breaker rating. That number is 80% of the breaker size for a continuous load.

50A breaker = 40A charger
40A breaker = 32A charger
60A breaker = 48A charger

What charger efficiency should I use for DC fast charging?

Use 90–95%. DC stations lose less inside the car because they skip the onboard charger, but the station itself loses some power. For home AC, 85–95% is normal. Older Level 1 setups can be closer to 80–85%.

Does the cost include public charger session or idle fees?

No. The cost is only energy times your rate. Many public stations add a session fee, a per-minute fee, or an idle fee after you finish. Add those on top of the number shown.

How do I model charging with my own solar power?

Change the electricity rate to what your solar power really costs you. Most home solar works out to about $0.05–$0.10 per kWh over the system's life. If you would otherwise export that power, use your export credit rate instead.

What rate should I enter if I have time-of-use pricing?

Enter the rate for the hours you plan to charge. Night rates are often $0.08–$0.12 per kWh, while peak afternoon rates can top $0.40. Set the start time to match, then compare runs to see the savings.

Does the temperature setting change how far I can drive?

No. It only slows the charging speed. Real winter driving range also drops, often 10–30%, because of heating and cold air. Lower the real-world range box yourself if you want winter driving numbers.

Is the gas savings number a promise?

No. It is a side-by-side comparison for the same distance using the price and MPG you type in. Real savings change with fuel prices, your power rate, and how you drive.

Why does cost per mile change when I switch to kilometers?

Because a kilometer is shorter than a mile. The same charge covers more kilometers than miles, so the cost per unit drops by about 38%. The total cost stays the same.

Does picking CCS, NACS, or CHAdeMO change my result?

No. The connector name is only a label. Speed comes from the station power and your car's DC limit. An adapter does not add power, though some adapters do lower the max current.

Why is my average power lower than the peak power?

On DC, the rate drops above 80%, so the average across the whole session falls below the peak. Cold or hot battery settings lower it as well. On AC, the average and peak match because the rate is flat.

What target charge is best for battery life?

Set 80% for daily use and go to 100% only before a long trip. Try not to sit at very low or very full charge for days. Many cars let you set this limit in the app so it happens on its own.

Why does my Level 1 charge take all night and still not finish?

A 120V outlet gives only about 1.2–1.4 kW. That adds roughly 3–5 miles per hour. Filling 60 kWh at that speed takes about two days, which is why most EV owners add a 240V circuit.