Why this matters
Most coverage of electric vehicles compares EPA-rated efficiency numbers, not actual fuel costs. Those ratings obscure the real question for drivers: what does it cost per mile to move my car, right now, in my state?
Two forces collided in early 2026 to make this comparison unusually interesting. Electricity prices have risen sharply across the Northeast and parts of California over the past two years — in some states, residential rates have climbed 25–40%. At the same time, disruption in the Strait of Hormuz (starting late February 2026) sent gasoline prices to roughly 35% above their January baseline. Both fuels are expensive right now, but the relative cost has shifted in ways that surprise most people: in several states, you now save money by running a plug-in hybrid on gasoline rather than charging it.
This calculator cuts through the EPA MPGe framing to show the real per-mile cost for each fuel in every state.
Core formula
For each state we compute a cost per mile for each fuel:
- Gas ¢/mi = gas price ($/gal) ÷ MPG × 100
- Electric ¢/mi = electricity rate (¢/kWh) ÷ efficiency (mi/kWh)
The Annual Diff column is the full-year cost difference between running all miles on gas versus all miles on electricity:
Annual Diff = (Gas ¢/mi − Electric ¢/mi) × miles/year ÷ 100
Positive = electric is cheaper over a full year. Negative = gas is cheaper. The % driven electric input does not affect this comparison — it affects the mixed-mode annual cost shown in the Gas $/yr and Elec $/yr columns, which reflect your actual spending given how much you charge.
Default vehicle
Toyota RAV4 Prime PHEV: 38 MPG in gas mode, 3.3 mi/kWh in electric mode. These are EPA-rated values. Real-world figures vary with driving style, temperature, and terrain — use the override fields to enter your own numbers.
Data sources
| Data | Source | Date | Updated | Link |
|---|---|---|---|---|
| Current gas prices | AAA state averages | Apr 27, 2026 | Daily | gasprices.aaa.com |
| Pre-conflict baseline | AAA state averages | Jan 2026 | Static snapshot | gasprices.aaa.com |
| Electricity rates | EIA via ElectricChoice.com | Apr 2026 | Monthly | electricchoice.com |
| Vehicle defaults | Toyota RAV4 Prime EPA specs | — | Static | fueleconomy.gov |
| State populations | US Census Bureau | 2024 estimates | Annual | census.gov |
Important assumptions and caveats
Home charging losses
Real-world home charging is approximately 85–90% efficient due to battery and inverter losses. This calculator assumes 100% efficiency. Your actual electric cost per mile is roughly 10–15% higher than shown. To account for this, try dividing your mi/kWh by 0.87 in the override field.
Public vs. home charging rates
This site uses residential electricity rates. DC fast charging typically costs 30–50¢/kWh — two to four times more than home rates in most states. PHEVs rarely use public charging (their batteries charge quickly at home overnight), so residential rates are the appropriate baseline for this vehicle class.
Time-of-use rates
Many utilities offer EV-specific overnight rates well below the residential average — sometimes as low as 5–8¢/kWh. Drivers on those plans will see substantially lower electric ¢/mi than shown. We use state average residential rates because TOU plan adoption varies widely. Use the electricity override field to enter your actual rate.
Marginal vs. average rates
EIA reports average residential rates. Your marginal rate — the cost of each additional kWh — may be higher, especially if you're on a tiered plan and charging pushes you into a higher tier.
Gas grade
AAA reports regular unleaded prices. The RAV4 Prime recommends premium fuel, which adds approximately 50–60¢/gal in most states. To compare accurately, add your local premium premium to the gas price override.
MPG vs. MPGe
EPA's MPGe metric converts kWh to "gasoline equivalent" using 33.7 kWh per gallon. This tells you how energy-efficient an EV is relative to gas — but says nothing about the cost of that energy. A 100 MPGe car in Massachusetts (electricity at 31.5¢/kWh) costs more per mile than a 38 MPG car running on $2.86/gal gasoline in the same state. Cost per mile is the metric that matters to drivers.
Why MPGe is misleading
The EPA introduced MPGe to give EV buyers a familiar yardstick. The conversion is based on the energy content of a gallon of gasoline (33.7 kWh), not its price. When electricity and gasoline trade near historical price ratios, this approximation works reasonably well. When electricity prices spike in a region, or when gas prices collapse, MPGe scores become actively misleading: a car with a high MPGe rating may cost more per mile to operate than a car with a lower one.
The correct comparison is always: (fuel unit price) ÷ (efficiency in that fuel's units) = cost per mile. This calculator does that directly.
Example: Massachusetts, January 2026 — electricity at 31.51¢/kWh, gas at $2.86/gal. RAV4 Prime: 3.3 mi/kWh electric, 38 MPG gas. Electric cost: 9.55¢/mi. Gas cost: 7.53¢/mi. The 94 MPGe-rated electric mode costs 27% more per mile than gasoline in this state at these prices.
How to use the calculator
- Enter your real-world MPG and electric efficiency, or use the RAV4 Prime defaults.
- Enter your annual mileage.
- Set the percentage of miles you drive electric. For PHEVs this typically ranges from 40–80% depending on commute length and charging access. Owners who charge every night and drive short distances may be 80%+ electric; those with long highway commutes may be closer to 40%.
- Toggle between Current prices (Apr 2026, ~35% above normal due to Strait of Hormuz disruption) and Pre-conflict baseline (Jan 2026, national avg ~$2.81/gal) to see how the comparison shifts.
- Use the price override fields to enter your own utility rate or local gas price for a personalized comparison.
- Use the Copy link button to share your specific scenario — the URL encodes all your inputs.