How to Calculate EV Charging Costs: The Simple Formula

Quick answer: Divide your monthly miles by your EV’s efficiency (miles per kWh), then multiply by your electricity rate ($/kWh). Formula: (miles ÷ mi/kWh) × $/kWh = charging cost. Add ~10% for charging losses on home AC charging. Example: 1,000 miles at 3.5 mi/kWh and $0.17/kWh costs about $53/month at home.

The three numbers you need

1. Your electricity rate ($/kWh). Check your utility bill or your utility’s website. The U.S. residential average was about $0.17/kWh as of mid-2025 (EIA data), but rates vary enormously by state and time of day.
2. Your EV’s efficiency (miles/kWh). Find it on the EPA label, the fueleconomy.gov site, or your car’s trip computer. Most modern EVs land between 3 and 4 miles/kWh; efficient models exceed 4, large trucks dip toward 2.
3. Your monthly mileage. The U.S. average is roughly 1,000–1,200 miles per month (about 12,000–14,000 per year).

The formula, step by step

Step 1: kWh needed = miles driven ÷ efficiency (mi/kWh)
Step 2: Add charging losses — multiply by ~1.10 for home AC charging (about 10% of energy is lost as heat in the onboard charger and cable). Public DC fast charging bills you for delivered energy, so skip this adjustment there.
Step 3: Cost = adjusted kWh × your rate ($/kWh)

Worked example: home charging

A driver covers 1,000 miles/month in an EV rated at 3.5 mi/kWh, paying $0.17/kWh at home. (Using the EIA 2025 national average of ~17.3¢/kWh gives essentially the same result — about a dollar more.)

• 1,000 ÷ 3.5 = ~286 kWh
• 286 × 1.10 (losses) = ~314 kWh from the wall
• 314 × $0.17 = ~$53/month

Worked example: mostly DC fast charging

Same driver, but relying on public fast chargers at $0.50/kWh:

• 1,000 ÷ 3.5 = ~286 kWh (no loss adjustment — billed on delivered energy)
• 286 × $0.50 = ~$143/month

Same miles, nearly triple the cost. This is why where you charge matters as much as what you drive — see our DC fast charging vs. home charging comparison.

Cost per mile: the number that lets you compare anything

Cost per mile = $/kWh ÷ mi/kWh. A few 2025 reference points (national averages):

Scenario	Math	Cost per mile
EV, home charging	$0.17 ÷ 3.5 mi/kWh	~$0.05
EV, public DC fast	$0.50 ÷ 3.5 mi/kWh	~$0.14
Gas car, 25 mpg at $3.10/gal	$3.10 ÷ 25	~$0.12
Hybrid, 50 mpg at $3.10/gal	$3.10 ÷ 50	~$0.06

Home-charged EVs typically run at roughly half the per-mile fuel cost of a conventional gas car. Heavy fast-charging use narrows the gap to roughly parity with an efficient gas car — before factoring in the EV’s lower maintenance costs.

Finding your real electricity rate

• Your bill. Divide the total electric portion of your bill by kWh used — this captures delivery charges, not just the supply rate. Many people underestimate their true rate by looking at supply alone.
• Time-of-use (TOU) plans. Many utilities offer EV or overnight rates far below the standard rate — sometimes under $0.10/kWh overnight versus $0.30+/kWh at peak. If you charge at night, a TOU plan is often the single biggest lever on your charging cost.
• State averages. The EIA publishes state-by-state residential rates; your state’s average is a reasonable stand-in if you haven’t checked your bill.

Adjusting for the real world

• Winter. Cold weather cuts efficiency 20% or more (see our cold-weather range guide), which raises cost per mile proportionally.
• Highway driving. EVs are most efficient in city driving; sustained 75+ mph highway cruising can drop efficiency 15–25% versus the EPA combined rating.
• Free charging. Workplace, municipal, or promotional free charging lowers your blended rate — count those miles at $0.
• Blended rates. Most drivers mix sources. Compute each share separately: (home miles cost) + (public miles cost), then divide by total miles for your true per-mile figure.

Worked example: three drivers, three bills

The formula is simple; the inputs are personal. Here’s how it plays out for three typical drivers, each doing 1,000 miles a month at 3.5 mi/kWh:

Driver A: suburban homeowner, overnight charging

Charges exclusively at home on a time-of-use overnight rate of $0.10/kWh. Energy needed: 1,000 ÷ 3.5 = 286 kWh, plus 10% losses = ~314 kWh. Monthly cost: 314 × $0.10 = ~$31. This is the EV best case — and it’s the most common case, since most owners charge at home.

Driver B: apartment renter, public charging mix

No home charger. Uses workplace Level 2 (free) for ~40% of miles and public DC fast charging at $0.50/kWh for the rest. Free miles cost $0; paid miles: 600 ÷ 3.5 = 171 kWh × $0.50 = ~$86/month. Still below the ~$124/month fuel bill of a 25-mpg gas car at $3.10/gal — but the free workplace charging is doing heavy lifting.

Driver C: sales rep, mostly fast charging

Covers 2,000 miles a month, 80% on DC fast chargers at $0.55/kWh. Paid energy: 1,600 ÷ 3.5 = 457 kWh × $0.55 = ~$251/month. At this extreme, fuel savings vs. gas shrink to nearly zero — the lesson being that EVs reward home charging, and high-mileage drivers without it should run these numbers carefully before buying.

The pattern: where you charge matters more than what you drive. Two identical EVs can differ 5× in running costs depending on the driver’s charging mix. Our home EV charging cost guide digs into installation costs and tariffs that unlock Driver A’s numbers.

EV charging costs in the UK, Canada and Europe: the same formula, local numbers

The three-number formula works everywhere — only the rate changes. Here are monthly home-charging costs for a typical driver (1,000 miles / ~1,600 km per month, 3.5 mi/kWh, +10% charging losses = ~314 kWh from the wall), using verified residential rates:

Market	Home rate (verified)	Monthly home-charging cost	Notes
USA	~17.3¢/kWh (EIA 2025 avg)	~$54	State variation is huge — check your utility; overnight TOU rates can halve this
UK — standard tariff	26.32p/kWh (Ofgem Oct–Dec 2026 cap, Direct Debit avg)	~£83	Varies by region and payment method; this is the England/Scotland/Wales average
UK — overnight EV tariff	~7–9p/kWh	~£25	The single biggest lever on UK charging costs — roughly a third of the standard-tariff bill
Canada — national avg	~14–16¢/kWh	~C$47	Provincial spreads are wide; Ontario TOU 10.3–20.3¢, BC two-tier 9.75¢/14.08¢, Alberta ~16.7¢
Canada — Quebec	~7–8¢/kWh (hydro)	~C$24	Among the cheapest EV running costs in the world
Europe — EU avg	~€0.29/kWh (Eurostat)	~€91	National variation dominates: see below
Germany	~€0.36–0.39/kWh	~€118	Europe’s expensive end — efficiency and overnight tariffs matter most here
France	~€0.22–0.27/kWh	~€77	Regulated tariffs keep prices moderate
Nordics	~€0.16–0.18/kWh	~€53	Cheap, often dynamic spot pricing rewards flexible overnight charging

A few things jump out. The UK overnight tariff is transformative — £25/month undercuts even Quebec. Germany is the market where EV fuel savings are thinnest, which is precisely why German buyers scrutinize efficiency ratings most. And everywhere, the formula’s first input — your actual rate, from your actual bill or tariff — beats any national average. Averages plan; bills decide.

For the full picture beyond fuel — insurance, maintenance, depreciation — see our EV vs gas true cost of ownership comparison.

Per-mile showdown: EV vs. petrol across markets

Cost per mile (or per km) is the universal comparator. Using the home-charging figures above at 3.5 mi/kWh:

Market	EV home-charging cost per mile	How it typically compares to petrol
USA	~$0.05	Roughly half the per-mile fuel cost of a 25-mpg gas car at recent prices
UK (standard tariff)	~£0.08 (8.3p)	Usually well under half the per-mile cost of petrol — UK pump prices make the EV advantage large
UK (overnight tariff)	~£0.025 (2.5p)	Annihilates petrol on running costs; among the cheapest motoring per mile anywhere
Canada (avg)	~C$0.05	Comfortably below gasoline per km in most provinces
Germany	~€0.12	Still typically beats petrol per km, but the margin is slimmer — efficiency matters
Nordics	~€0.05	Decisively cheaper than petrol per km

To make the petrol side of this comparison for your own situation, use the same method: local pump price per litre ÷ your car’s km per litre (or per gallon ÷ mpg). The EV side of the ledger is the three-number formula from this guide; the petrol side is one division. Drivers who do both calculations before buying almost never regret it.

Tools and apps that track your charging spend

Manual math gets you the estimate; these keep you honest afterward:

• Your car’s trip computer and app. Most EVs report lifetime mi/kWh (or kWh/100 km) — the efficiency input, measured from your actual driving rather than a lab rating.
• Utility bill + a simple spreadsheet. Total electric bill ÷ kWh used = your true all-in rate including delivery charges. One row per month beats any amount of theorizing.
• Smart charger apps. Most networked home chargers log every session’s kWh and cost (once you enter your tariff), producing a monthly total automatically.
• Charging network apps. Your public-charging history with per-session costs lives in each network’s app — export it quarterly to compute your true blended rate across home and public.
• Receipt discipline for reimbursement. If you charge at work or claim mileage, keep the session records — many employers reimburse home charging for fleet or company EVs at the local residential rate.

Revisit the numbers twice a year: tariffs change, seasons swing efficiency ~20%, and a five-minute recalculation keeps the “EVs are cheap to run” claim true rather than assumed. Drivers who track one full year of real data — winter and summer, home and public — end up with a personal cost-per-mile figure no national average can match, and that figure is the one to use when the next car purchase comes around.

Five mistakes that wreck your estimate

Most bad EV cost estimates come from the same handful of errors:

1. Using the supply rate instead of the all-in rate. Your bill has delivery charges, fees and taxes on top of the advertised supply price. Divide the total electric portion of the bill by kWh used — the true rate is often 30–50% higher than the supply number.
2. Forgetting charging losses. About 10% of the energy you pull from the wall never makes it into the battery on AC charging (heat in the onboard charger and cable). Skip the ×1.10 adjustment and every estimate comes out optimistically low.
3. Using the brochure efficiency. EPA/WLTP figures are lab numbers. Your real mi/kWh — from the trip computer after a month of your driving, in your climate — is the honest input. Highway-heavy drivers should expect 15–25% worse than the combined rating.
4. Ignoring winter. Cold weather cuts efficiency ~20% or more, which raises cost per mile proportionally. If you’re estimating annual costs, blend a winter and summer efficiency figure rather than using one number.
5. Pricing 100% of miles at the home rate. Road trips, forgotten plug-ins and apartment living mean some miles always cost public-charging prices. A realistic blend — say 80% home, 20% public — beats a fantasy 100% home figure every time.

Correct those five and your estimate will land within a few percent of your actual bills — which is precisely the level of accuracy that makes the buy-or-not decision trustworthy. And when a dealer quotes you a rosy running-cost figure, you’ll have the three-number formula ready to check their math on the spot.

Sources

• EnergySage — Home vs. public EV charging (EIA rate data, 2025)
• ChargingAdvisor — Home vs. public charging cost comparison
• U.S. DOE/EPA — FuelEconomy.gov (official efficiency ratings)
• U.S. DOE Alternative Fuels Data Center

Frequently asked questions

How much does it cost to charge an EV per month?

For a typical driver (1,000 miles/month) charging at home on the national average rate, roughly $50–$60/month. On public fast chargers, the same driving can cost $130–$160/month. Your rate and efficiency move these numbers significantly — which is exactly why running the three-number formula beats guessing.

What’s the formula for EV charging cost?

(Monthly miles ÷ vehicle efficiency in mi/kWh) × electricity rate in $/kWh, plus ~10% for charging losses on home AC charging. That’s it — three inputs.

Is it cheaper to charge an EV at night?

Often yes. Many utilities offer time-of-use rates with cheap overnight pricing. Charging on an off-peak rate can cut your per-kWh cost dramatically compared to daytime peak rates.

How do I find my EV’s efficiency in miles per kWh?

Check the EPA label on the window sticker, look it up on fueleconomy.gov, or read it from your car’s trip computer after a few weeks of normal driving — the car’s own number reflects your actual driving style.

Does charging to 100% cost more than charging to 80%?

Per kWh, no — you pay for energy delivered either way. But on per-minute-priced public chargers, the slow taper above 80% means you pay more per unit of energy gained. At home on a flat rate, it makes no difference.

How much does it cost to charge an EV in the UK per month?

For a typical 1,000 miles/month driver: roughly £83/month on the standard variable tariff (26.32p/kWh under the Oct–Dec 2026 Ofgem cap), or roughly £25/month on a dedicated overnight EV tariff (~7–9p/kWh). The tariff you choose matters more than the car you drive — switching to an overnight rate is the single biggest saving available to UK EV owners.

How much does it cost to charge an electric car in Canada?

At the national average of ~14–16¢/kWh, about C$47/month for 1,000 miles of home charging. Provincial differences are dramatic: Quebec’s hydro power (~7–8¢/kWh) brings it to roughly C$24/month, while Ontario time-of-use rates (10.3–20.3¢/kWh) reward overnight charging. Check your provincial utility’s EV rate before estimating.

Is charging an EV cheaper than petrol in Europe?

Almost always, on a per-km basis — but the margin varies. In France (~€0.22–0.27/kWh) or the Nordics (~€0.16–0.18/kWh), home-charged EVs cost a fraction of petrol per km. In Germany (~€0.36–0.39/kWh) the advantage is slimmer, so efficiency (kWh/100 km) and overnight tariffs matter more. Run both sides — (km ÷ efficiency) × your rate versus pump price ÷ your car’s consumption — with local numbers.

The bottom line: Three numbers — your rate, your efficiency, your miles — tell you exactly what an EV costs to run. For most drivers charging at home, the answer is roughly $50–$60 a month: about half the fuel cost of a comparable gas car. Run your own numbers before you buy, and keep them honest with your real utility rate. More in Buying Guides.