The comparison that actually matters is cost per mile, and both sides of it are one division each:

EV: $/mile = price per kWh ÷ miles per kWh    Gas: $/mile = $ per gallon ÷ mpg

Everything else — rates, efficiency, geography, season — is an argument about which numbers to plug in.

Real numbers for the EV side

Two inputs, each with an honest range:

Price per kWh. US residential electricity averages roughly $0.17–0.18 all-in (EIA data, 2025), but the spread is wide: under $0.12 in the Southeast and Midwest, above $0.30 in California and parts of New England. EV-specific and time-of-use plans undercut the average — overnight charging at $0.08–0.12 is common where offered. Public DC fast charging runs $0.30–0.60/kWh depending on network, region and membership.

Miles per kWh. EPA-style figures: ~4.0+ for efficient sedans, ~3.3–3.7 for mainstream crossovers, ~2.2–2.8 for trucks and three-row SUVs. Cold weather takes 20–30% off; highway speed takes some more.

Scenario	$/kWh	mi/kWh	Cost/mile
Home, average US	$0.17	3.5	4.9¢
Home, cheap overnight plan	$0.10	3.5	2.9¢
Home, California-tier rates	$0.30	3.5	8.6¢
DC fast, typical network	$0.45	3.5	12.9¢
DC fast, truck/SUV, winter	$0.50	2.5	20.0¢

Real numbers for the gas side

A 30 mpg car on $3.50 gas costs 11.7¢/mile. A 25 mpg SUV at $3.80 runs 15.2¢/mile; a 45 mpg hybrid at $3.50 manages 7.8¢. The EPA fleet average hovers near 27–28 mpg for new vehicles.

The honest comparison

Home charging wins almost everywhere: even at California-tier $0.30/kWh an efficient EV roughly matches a frugal hybrid, and at average US rates it’s a third to a quarter the cost of a comparable gas car. The pattern only inverts in one place — expensive DC fast charging feeding an inefficient vehicle in bad weather, where 20¢/mile electrons lose to 12¢/mile gasoline. Which is fine, because that’s not where most kWh flow: the typical EV owner does 80–90% of charging at home overnight and uses DC on road trips, where the premium buys time rather than savings.

The breakeven formula, if you want it exactly: a DC station’s $/kWh matches a 30-mpg car on $3.50 gas when price = 0.117 × mi/kWh — about $0.41/kWh at 3.5 mi/kWh. Above that, the gas car is cheaper per mile; below it, the EV wins.

What the math leaves out

Three things honest comparisons mention:

• Charging losses — the wall delivers ~10–15% more energy than the battery receives on AC. The calculator prices drawn energy; if you do napkin math, inflate home kWh by ~12%.
• Fees that aren’t energy — session fees, per-minute billing, idle fees, and demand charges folded into commercial DC pricing. The $0.45 sticker isn’t always the whole bill.
• Maintenance and depreciation — real total-cost-of-ownership comparisons include them; this site deliberately stays on the energy line, where the arithmetic is clean.

The takeaway isn’t “EVs always win” — it’s that where the electrons come from matters as much as how many you use. Charge at home and it’s not close; road-trip exclusively on premium-priced DC and the advantage largely evaporates.

Frequently asked questions

Is charging an EV always cheaper than gas?

At home, almost always — $0.15/kWh and 3.5 mi/kWh is about 4.3¢/mile against ~12¢ for a 30 mpg car on $3.50 gas. On DC fast charging at $0.45–0.60/kWh it's often a wash or slightly worse — you're paying for speed and infrastructure, not savings.

How do I find my real home electricity rate?

Total amount due ÷ total kWh on your last bill — that folds delivery charges, riders and taxes into one honest number. Then check for EV or time-of-use plans: many utilities offer overnight rates of $0.08–0.12/kWh specifically for charging.

Why do networks charge per minute in some states?

Legacy rules in some jurisdictions restricted per-kWh electricity resale to utilities, so networks billed by time instead. Many states have since allowed per-kWh pricing, but per-minute sites still exist — at 50 kW a per-minute price is a much worse deal than at 150 kW.

Does cold weather change the math?

Yes — cabin heat and a cold-soaked battery can cut efficiency 20–30%, raising $/mile proportionally. A winter figure of 2.6 mi/kWh on an EV that does 3.5 in spring is normal for short trips in real cold. Preconditioning while plugged in helps.

What about free charging — is it really free?

Where it exists (some employers, hotels, dealers) it's genuinely free to you, but it's usually Level 2 — the 'price' is your time. Free DC fast charging from vehicle purchase programs does exist (some makers bundle 2–3 years); those plans are worth real money on road trips.