Charging Session Pricing

Estimate the cost of a public charging session. Compare per-kWh vs per-minute rates.

What this calculator does

Estimate the total cost of a charging session under per-kWh, per-minute, or mixed pricing models. It also shows energy delivered and an effective rate per kWh so you can compare stations on equal terms.

Inputs explained

Pricing model: Per kWh, per minute, or mixed (fee + kWh + minute).
Charger power: Estimated charging power in kW.
Session duration: Total charging time in minutes.
Price per kWh: Energy price for per-kWh or mixed models.
Price per minute: Time price for per-minute or mixed models.
Session fee: Fixed start fee in mixed pricing.

How it works / Method

Convert session duration into hours.
Compute energy delivered as power times hours.
Apply the selected pricing model to calculate total cost.
Divide total cost by energy delivered to get the effective rate.

Formula(s) used

hours = minutes / 60

energy_kWh = power_kW * hours

cost_kWh = energy_kWh * price_per_kWh

cost_min = minutes * price_per_min

cost_mixed = fee + cost_kWh + cost_min

effective_rate = total_cost / energy_kWh

Assumes constant power during the session.

Inputs

Currency

Pricing Model

Average Power (kW)

Required to estimate Energy if only Time is known.

Duration (Minutes)

Session Cost

Total Cost -

Energy Delivered (Est.) -

Effective Rate ($/kWh) -

Step-by-step example

Example inputs: 50 kW charger, 30 minute session, price $0.40 per kWh (per-kWh model).

Energy delivered: 50 * (30 / 60) = 25 kWh.
Total cost: 25 * $0.40 = $10.00.
Effective rate: $10.00 / 25 = $0.40 per kWh.

Use cases

Compare per-minute and per-kWh pricing across stations.
Estimate total cost before starting a public charging session.
Evaluate whether a station fee changes the effective rate.
Compare different charger power levels for cost efficiency.
Estimate cost for a time-limited charging stop.
Translate session pricing into a usable per-kWh rate.

Assumptions & limitations

Charging power is treated as constant during the session.
Does not include idle fees after charging ends.
Does not model demand charges, taxes, or memberships.
Real sessions often taper at higher state of charge.
Energy delivered depends on vehicle acceptance limits.
Results are estimates for planning, not a final bill.

Disclaimer: Results are estimates for planning only. Actual pricing can vary by station and network policies.

Frequently Asked Questions

What is the effective rate per kWh?

The effective rate converts any pricing model into a single cost per kWh. It divides the total session cost by the energy delivered. This lets you compare stations that charge per minute or add a session fee with stations that charge per kWh. A higher effective rate means you are paying more for the same energy.

Why can per-minute pricing be more expensive?

Per-minute pricing does not account for energy delivered. If your vehicle charges slowly or the station is limited, you pay more for fewer kWh. This is common when charging power tapers at higher state of charge. The effective rate helps reveal when per-minute pricing is actually more expensive than per-kWh pricing.

Does this include idle fees?

No. Idle fees are charged after a session ends to discourage occupying a charger. This tool focuses only on energy and time during the active session. If idle fees apply at your station, add them separately or estimate extra minutes at the idle fee rate.

How do I choose a charger power value?

Use the charger or vehicle display when possible. If you only know the station rating, pick a realistic average power rather than the maximum. Many vehicles charge at lower power as the battery fills. Choosing an average power will produce a more realistic cost estimate for the session.

What if pricing is both per kWh and per minute?

Select the mixed pricing model and enter the session fee, per-kWh price, and per-minute price. The calculator adds all components together, then computes the effective rate. This is useful for networks that apply a connection fee plus energy and time charges.

Why does my final bill differ?

Real sessions can vary in power, include taxes, or add idle fees. Some networks also round durations or add membership discounts. The calculator assumes a steady average power and no extra fees beyond the selected model. Use the station receipt to refine your input values for future sessions.

Sources & references

U.S. Energy Information Administration: Measuring electricity - Defines kW and kWh for power and energy.
DOE Alternative Fuels Data Center: EV charging options for consumers - Charging level power ranges and typical use.
U.S. EPA: Plug-in electric vehicle charging basics - Notes how charging power can change over a session.
Schema.org: FAQPage, WebPage, and BreadcrumbList - Structured data definitions used on this page.