FleetOpsClub logo
FleetOpsClub
Categories

EV Charging Cost Calculator

Cost a charging month from miles, efficiency and your rate, with charging losses and the depot demand charge both modelled rather than left out.

Independently built and reviewed by the FleetOpsClub research team. Published October 8, 2026. Last verified October 8, 2026.

Calculate Your Charging Cost









The formula

Battery kWh = Miles ÷ Efficiency (mi/kWh)

Billed kWh = Battery kWh ÷ (1 − Charging Loss)

Cost = Billed kWh × $/kWh  +  Peak kW × $/kW-month

Two of those four terms are missing from every other charging calculator we could find, and they are the two that decide whether a depot pencils out.

Charging losses: what we can and cannot verify

You are billed for energy at the meter. The battery receives less than that, so a calculator that multiplies battery kWh by your rate understates the bill. The honest question is by how much, and here is exactly how far the evidence goes.

What is verifiable at a primary source is the charger, not the whole path. EPA’s ENERGY STAR programme work on EV charging infrastructure publishes measured equipment efficiency: 98% for an AC Level 2 charger at 7.2 kW, and 92–97% for DC fast chargers at 50 kW and 350 kW, with the AC-to-DC conversion stage named as the main source of loss.

That figure covers the charging station alone. On an AC Level 2 charge the AC-to-DC conversion happens in the vehicle’s onboard charger, which the equipment number does not measure, and battery and thermal losses sit beyond it again. We could not verify a wall-to-battery loss range at a primary source, so the 10% default in the field above is a planning assumption and is labelled as one. It is not a measured figure and this page will not dress it up as one.

The number that is actually yours is in your own records: billed kWh from the utility statement against odometer miles for the same period gives you a real figure for your vehicles, your climate and your chargers. An EV charging log is where that comes from. One caution if you are reconciling against a window sticker: EPA’s own definition of the label’s kWh-per-100-miles is “the estimated rate of fuel consumption… for combined city and highway driving”, tied to expenditure on electricity, and EPA does not state on that page whether charging losses are inside it. If your efficiency figure already came from the wall, set losses to zero rather than counting them twice.

Demand charges, which decide depot economics

Commercial electricity has two prices. One is energy, in dollars per kWh, and it is the one every charging calculator models. The other is demand, in dollars per kW per month, billed on the single highest demand interval of the month regardless of how much you charged in total. Plug in six trucks at once and you have bought that peak for the whole month.

Two real published tariffs show the size of it. On PG&E’s Schedule B-10, the medium general demand-metered service for 75–499 kW, the demand charge is $20.50 per kW per month at secondary voltage, summer and winter alike, on the rate sheet effective 1 March 2026. A 150 kW depot peak on that schedule is $3,075 a month before a single kilowatt-hour is counted.

But the right schedule can remove the charge entirely, which is why this is an input and not a constant. PG&E’s Schedule BEV, for commercial EV charging metered separately from other load, states that the kW subscription component replaces the kW demand charge: BEV-2-S sells capacity in 50 kW blocks at $95.56 a block, or $1.91 per kW, with a $3.82 per kW overage fee. Same utility, same depot, an order of magnitude apart on the kW term. Before modelling a depot, find out which schedule you are on.

Staggering start times lowers peak kW without lowering kWh, which is why managed charging pays for itself on a demand-charge tariff and does nothing on an energy-only one.

Worked example

Fleet: ten electric vans, 25,000 miles between them in a month, 2.2 mi/kWh
Rate: $0.15/kWh  ·  Losses: 10% assumed
Depot: 150 kW peak at $20.50/kW-month

Into the battery: 25,000 ÷ 2.2 = 11,363.6 kWh
Billed at the meter: 11,363.6 ÷ 0.90 = 12,626.3 kWh
Energy cost: 12,626.3 × $0.15 = $1,893.94
Demand charge: 150 × $20.50 = $3,075.00
All-in: $4,968.94, or $0.1988 per mile — against $0.0758 per mile if you had counted energy alone.

The demand charge is 62% of that bill and two and a half times the cost per mile, which is the whole reason this calculator asks for peak kW. Note what happens as the depot fills up: the demand charge does not move when you drive more miles, only when you draw more kilowatts at once. Run 50,000 miles through the same 150 kW and the all-in figure falls to $0.1373 per mile. Depot charging gets cheaper per mile as utilisation rises, and that is a fact about the demand charge rather than about the vehicles.

Sources

All read at source on 8 October 2026.

P. Banwell (U.S. EPA), E. H. Myers, Z. Montero and S. Noblet, Driving Energy Efficiency into North American Electric Vehicle Charging Infrastructure, 2020 ACEEE Summer Study on Energy Efficiency in Buildings, Table 2, sourced to EPA 2018.  energystar.gov (PDF).

Pacific Gas and Electric Company, Electric Schedule B-10, Medium General Demand-Metered Service, total demand rate $20.50/kW, sheet effective 1 March 2026.  pge.com (PDF).

Pacific Gas and Electric Company, Electric Schedule BEV, Business Electric Vehicles, Rates sheet 2 and Special Conditions item 6.  pge.com (PDF).

U.S. EPA, Interactive Version of the Electric Vehicle Label, definition of kWh per 100 miles.  epa.gov.

U.S. Energy Information Administration, Gasoline and Diesel Fuel Update, for the diesel comparison: $6.199/gal, week ending 10/05/26.  eia.gov/petroleum/gasdiesel.

Related tools

Record the sessions this calculator models with the EV charging log template, compare electric against diesel across a whole fleet with the EV fleet savings calculator, or price the diesel side on its own with the fleet fuel cost calculator.

Frequently asked questions

Quick answers to the questions buyers usually ask once the category, software, or rollout details start getting more specific.

A

Divide miles by efficiency in miles per kWh to get the energy the battery needs, divide that by one minus your charging loss to get the kWh the meter will bill, then multiply by your rate. If you charge at a depot on a commercial tariff, add peak kW multiplied by your demand charge — on some tariffs that second term is larger than the first.

A

The 10% default here is a planning assumption, not a measured figure, and we say so because we could not verify a wall-to-battery range at a primary source. What is verifiable is the equipment: EPA's ENERGY STAR work puts an AC Level 2 charger at 98% efficient and DC fast chargers at 92–97%, but that covers the station only, not the vehicle's onboard charger or the battery. Replace the default with billed kWh against odometer miles from your own records as soon as you have a month of them.

A

It is a second price on commercial electricity, billed in dollars per kW per month on the single highest demand interval of the month rather than on total consumption. PG&E's Schedule B-10 charges $20.50 per kW per month at secondary voltage. A 150 kW depot peak on that schedule costs $3,075 a month before any energy is billed, which is why it can dwarf the per-kWh cost and why no honest depot model leaves it out.

A

Sometimes, by being on the right tariff. PG&E's Schedule BEV, for commercial EV charging on a separate meter, replaces the demand charge with a kW subscription — $95.56 per 50 kW block on BEV-2-S, which works out at $1.91 per kW against $20.50 on the general commercial schedule. Beyond the tariff, staggering start times lowers peak kW without lowering kWh, so managed charging pays on a demand-charge rate and does nothing on an energy-only one.

A

Three reasons, in order of size: a demand charge you are not counting, charging losses between the meter and the battery, and real efficiency being below the rated figure in cold weather or under load. The first is usually the largest and is the one almost no calculator models.

A

Enter your MPG and diesel price above and this calculator works the same miles both ways. Diesel cost is miles divided by MPG multiplied by dollars per gallon — the EIA weekly national average was $6.199 a gallon for the week ending 5 October 2026. Compare against the all-in electric figure including demand charges, not the energy-only one, or the comparison flatters electric.

Browse categoriesCompare software

Need more fleet management tools? Browse all calculators or explore fleet management software.