EV Home Charging Cost Calculator
Work out the cost to charge an EV at home from battery size, state-of-charge range, charger efficiency, and your electricity price — plus cost per mile vs petrol. Free.
EV Home Charging Cost Calculator
Charging at home is where EVs save the most money. Enter your battery size, how far you're topping up, your charger's efficiency, and your electricity rate to see the cost of a charge, the cost per mile, and how it compares to running a petrol car.
How to Use the EV Charging Cost Calculator
Enter your battery and charge range
Your battery's usable capacity in kWh, and the state-of-charge you're charging from and to. Most owners cycle in a daily band (often 20–80%) to protect battery longevity rather than charging to 100%.
Set charger efficiency
Some energy is lost as heat between the wall and the battery. Level 2 home charging is typically around 85–92% efficient; the default 90% is a good estimate. This is why your meter shows more kWh than ends up in the battery.
Enter your electricity price
Use your per-kWh rate — and if you're on a time-of-use plan, the off-peak overnight rate, since that's when most home charging happens and where EVs save the most.
Compare to petrol
Enter your EV's efficiency (miles per kWh) and a petrol car's price and mpg to see the per-mile cost gap. Home-charged EVs typically cost a fraction of petrol per mile, which is the core of the savings case.
What It Really Costs to Charge an EV at Home
Energy In, Losses, and Cost
The cost of a home charge comes down to three numbers: how much energy you put in the battery, how much extra the grid delivers to cover charging losses, and what you pay per kilowatt-hour. The energy added to the battery is just your battery's capacity multiplied by the percentage you're charging — topping a 75 kWh battery from 20% to 80% adds 45 kWh. But the meter sees more than that, because charging isn't perfectly efficient: a Level 2 home charger loses roughly 8–15% of the energy as heat in the cables, onboard charger, and battery management, so to get 45 kWh into the battery the grid actually supplies around 50 kWh. Multiply that grid figure by your electricity rate and you have the true cost of the charge. At 16 cents per kWh, that 45 kWh top-up costs about eight dollars — and adds well over 150 miles of range for most EVs.
The headline EV value proposition lives in the cost per mile. Divide the charge cost by the miles that charge buys you, and home-charged electricity typically works out to a small fraction of what petrol costs per mile. An EV doing 3.5 miles per kWh on 16-cent power costs roughly 4–5 cents a mile, versus around 12 cents a mile for a 30-mpg petrol car at $3.50 a gallon — often less than half, and far less if you charge on a cheap overnight time-of-use rate. Over 12,000 miles a year, that gap is hundreds of dollars, and it's the single biggest running-cost advantage of an EV. The savings shrink (or vanish) if you rely on public DC fast charging, which can cost three to five times the home rate, which is why "do you have home charging?" is the most important question in the EV value equation.
"The EV savings story is really a home-charging story. On a cheap overnight rate the per-mile cost can drop below a nickel; on public fast chargers it can rival petrol. Where you plug in decides everything."
Time-of-Use, Battery Care, and the Global Picture
Two habits maximise the savings. First, charge on a time-of-use or EV tariff: many utilities offer steeply discounted overnight rates because EVs soak up off-peak grid capacity, and shifting your charging to those hours can halve the per-mile cost. Second, charge to a daily ceiling like 80% rather than 100% for routine use — it barely affects daily range, reduces battery degradation over the years, and charges faster since the last 20% slows down. The same arithmetic applies anywhere, only the rates and units change. In the United Kingdom and Europe you'd enter pence or euro-cents per kWh and litres rather than gallons; across Southeast Asia, EV adoption is rising fast in Singapore (where charging costs are compared against pump prices that include high duties) and Thailand and Indonesia, where government incentives are accelerating uptake. Wherever you are, the method is identical: figure the grid energy including losses, multiply by your rate, and compare the per-mile result to what the pump costs.
10 Facts About EV Charging Costs
Energy added = battery capacity × the % you charge (20→80% of 75 kWh = 45 kWh).
Charging loses ~8–15% as heat, so the grid supplies more than the battery receives.
Charge cost = grid energy × your price per kWh.
Home-charged EVs often cost 4–5¢ per mile versus ~12¢ for a 30-mpg petrol car.
Time-of-use rates overnight can roughly halve the per-mile cost.
Public DC fast charging can cost 3–5× the home rate, eroding the savings.
Charging to 80% daily protects the battery and charges faster than topping to 100%.
Miles per kWh (efficiency) varies ~2.5–4.5 by vehicle, weather, and speed.
Cold weather cuts efficiency — winter range and cost per mile both worsen.
"Do you have home charging?" is the biggest factor in EV running-cost savings.
Frequently Asked Questions
- Multiply the energy you add to the battery by your electricity rate, then add charging losses. Charging a 75 kWh battery from 20% to 80% adds 45 kWh; with ~90% charger efficiency the grid supplies about 50 kWh, so at 16¢/kWh the charge costs roughly $8 and adds well over 150 miles. Your exact cost depends on your battery size, charge range, and per-kWh price — enter them above for a precise figure.
- Charging isn't perfectly efficient. Energy is lost as heat in the charging cable, the car's onboard charger, and the battery itself, so some of the electricity you pay for never reaches the battery. Level 2 home charging is typically 85–92% efficient — the default 90% here means you pay for about 11% more energy than the battery gains. That's why your electricity meter shows more kWh than the car's display says was added.
- For home charging, usually less than half. An EV doing 3.5 miles per kWh on 16¢ electricity costs about 4–5¢ a mile, while a 30-mpg petrol car at $3.50/gallon costs about 12¢ a mile. On a cheap overnight time-of-use rate the EV can drop below 3¢ a mile. Over 12,000 miles a year that's hundreds of dollars saved. The advantage narrows if you rely on public fast charging, which costs much more than home power.
- For daily driving, most manufacturers recommend charging to around 80% to reduce battery degradation over the years; charge to 100% only before a long trip. The top 20% also charges more slowly. It costs the same per kWh either way, but staying in a daily band like 20–80% preserves long-term battery health and is why this calculator defaults to that range. Lithium batteries are happiest spending most of their life in the middle of the charge window.
- It's an EV's efficiency — how far it travels on one kilowatt-hour of energy, the electric equivalent of miles per gallon. Most EVs manage between about 2.5 and 4.5 mi/kWh depending on the vehicle, your speed, terrain, and temperature. Higher is better and means lower cost per mile. Your car's trip computer shows your real-world figure; cold weather, high speeds, and heavy loads all reduce it, which is why winter range drops.
- Yes, indirectly. Cold reduces an EV's efficiency (fewer miles per kWh) because of battery chemistry and cabin heating, and it can slow charging and increase losses. The price per kWh doesn't change, but you'll need more energy for the same distance in winter, raising the effective cost per mile. To model winter, lower the miles-per-kWh figure you enter — dropping from 3.5 to 2.8, for example, raises your cost per mile accordingly.
- Almost always. Home electricity typically costs a small fraction of public DC fast-charging rates, which can be three to five times higher and sometimes approach petrol's per-mile cost. Public charging buys convenience and speed for trips, but routine charging at home (especially on an off-peak rate) is where EVs save money. This is why access to home or workplace charging is the strongest predictor of whether an EV will be cheap to run for a given owner.
- Time-of-use (TOU) or dedicated EV tariffs charge different rates by time of day, with cheap overnight prices when grid demand is low. Since most home charging happens overnight, scheduling your car to charge during the off-peak window can roughly halve your per-mile cost. Many utilities offer special EV plans. Enter your off-peak rate in the calculator to see the savings — it's often the single biggest lever on EV running costs after simply having home charging at all.
- Yes — the energy math is universal. Enter your local electricity price per kWh (pence or euro-cents in the UK/EU, and so on) and, for the petrol comparison, your local fuel price and your car's economy. If you measure fuel in litres and economy in L/100km, convert to a per-mile or per-km basis to compare. EV adoption is rising fast across Singapore, Thailand, Indonesia and beyond; the calculator's method applies wherever you plug in — just use your own rates.
- It depends on your charger's power. A Level 2 home charger delivering around 7 kW adds roughly 7 kWh per hour, so a 45 kWh top-up takes about six to seven hours — easily done overnight, which is why home charging fits a daily routine so well. A standard wall outlet (Level 1, ~1.4 kW) is far slower and better suited to plug-in hybrids or light daily use. This calculator focuses on cost rather than time, but charging speed is why most owners plug in at night and wake up full.
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