What public electricity price makes a PHEV cheaper than gas?

Subtract fixed session fees from the cost of gasoline for the same miles, then divide the remainder by billed kWh. If fees alone exceed the gasoline cost, even free charging energy cannot save money.

Why can per-minute charging be expensive for a PHEV?

The billed charging time depends on the power your vehicle actually accepts over the session. Enter average accepted wall kW rather than the station's advertised maximum. Longer charging time raises cost when each minute is billed.

Can I use MPGe in the gasoline MPG field?

No. Enter miles per US gallon when the vehicle operates on gasoline. Electric consumption has its own battery kWh per 100 miles field.

Does this show whether buying a PHEV is worth it?

No. It compares energy costs for an entered charging session and the same driving distance on gasoline. Purchase price, financing, insurance, maintenance and depreciation are outside this calculation.

PHEV Public Charging vs Gas Calculator: Check Whether Charging Is Worth It

Inputs are illustrative. Use your PHEV's electric-only battery consumption, gasoline-mode MPG and current station prices. Average accepted power is not the charger's advertised maximum.

Station billingEnergy added to battery (kWh)Electric consumption at battery (kWh/100 miles)Charging efficiency (%)Average accepted wall power (kW)Station rate ($/kWh)Session, parking and idle fees ($)MPG when using gasoline (US)Gas price ($/US gallon)Identical charging sessions per week (0–100)

Charge or use gasoline?$1.41 more per charge

Charge $4.33 versus gas $2.92 for 33.33 electric-only miles.

11.11 billed kWh and approximately 202.02 charging minutes.

$7.05 extra per week at 5 identical sessions.

Break-even station rate: $0.1728 per kWh, including entered fees. Lower rates cost less than gasoline.

Cost for the same electric-only driving distance
Energy option	Session equivalent	Cost per mile
Public charge, including fees	$4.33	$0.130
Gasoline	$2.92	$0.088

Formula Wall kWh = battery kWh ÷ charging efficiency. Electric miles = battery kWh ÷ battery kWh/100 mi × 100. Charge cost = billed kWh × rate, or wall kWh ÷ average kW × 60 × minute rate, plus fees. Gas cost = same miles ÷ MPG × gas price.

Electric-only miles must be achievable without gasoline use. For blended operation, heating-related engine use or time billed after charging finishes, compare actual receipts instead. This tool excludes vehicle purchase and ownership costs.

Saved plans stay in this browser. Names and entered prices are not sent with calculator analytics.

Is public charging worth it for your PHEV?

Compare public electricity and gasoline for the same electric-only driving distance. Enter battery energy added, battery-side consumption, charging efficiency, gasoline-mode MPG and actual station fees. Per-minute billing uses average wall power accepted during the charge, which can be lower than either the station or vehicle maximum.

Worked example

An illustrative 10 kWh added to the battery at 90% charging efficiency requires 11.11 billed kWh. At 30 battery kWh per 100 miles, that energy covers 33.33 electric-only miles. A 40-MPG gas mode at $3.50 per gallon costs about $2.92 for those miles. Public charging at $0.30/kWh plus a $1 fee costs about $4.33, approximately $1.41 more using rounded session costs. At an average 3.3 kW, charging takes about 202 minutes before any extra idle time.

How to use the result

Use consumption measured at the battery, not wall consumption with losses already included; otherwise charging losses would be counted twice. The comparison assumes the electric miles can be driven without burning gasoline. For blended operation or engine use during heating, compare actual energy and fuel receipts. Fees are entered dollar totals, not predicted parking or idle charges. Weekly results assume identical sessions.

Sources and assumptions

DOE/EPA personalized plug-in hybrid calculator Accessed 2026-10-02

Calculation methodology. Worked examples use the expressly stated inputs; sample prices are illustrative rather than local quotes.

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Frequently asked questions

What public electricity price makes a PHEV cheaper than gas?: Subtract fixed session fees from the cost of gasoline for the same miles, then divide the remainder by billed kWh. If fees alone exceed the gasoline cost, even free charging energy cannot save money.
Why can per-minute charging be expensive for a PHEV?: The billed charging time depends on the power your vehicle actually accepts over the session. Enter average accepted wall kW rather than the station's advertised maximum. Longer charging time raises cost when each minute is billed.
Can I use MPGe in the gasoline MPG field?: No. Enter miles per US gallon when the vehicle operates on gasoline. Electric consumption has its own battery kWh per 100 miles field.
Does this show whether buying a PHEV is worth it?: No. It compares energy costs for an entered charging session and the same driving distance on gasoline. Purchase price, financing, insurance, maintenance and depreciation are outside this calculation.

Last updated 2026-10-02