Methodology and sources
Every calculator on this site starts from a default value. This page lists all of them, says where each one comes from, and says plainly which are sourced figures and which are assumptions. Nothing here is a claim about your vehicle or your electricity plan — the point of the calculators is that you replace these numbers with your own.
How to read this page
Each figure below is marked one of two ways.
- Sourced — the value is taken from a named external source, and that source is given.
- Assumption — the value is a reasonable working figure chosen to make the calculator useful out of the box. It is not measured, not surveyed, and not taken from a published dataset. Treat it as a starting point, not as evidence.
At the time of this review, the majority of the defaults on this site are assumptions. US electricity and fuel prices vary so widely by retailer, tariff, time of day, state and site that a single national figure would be misleading whichever number was chosen. Rather than attach a citation that does not really support the number, the figures are labelled honestly and every one of them is editable in the calculator.
All defaults live in one file, assets/js/pricing-data.js. The values below are read from that file. If a figure on a calculator disagrees with this page, the file is the source of truth and this page is out of date — please say so.
Electricity price tiers
Six price tiers appear in the rate comparison on every cost calculator. They are round numbers chosen to span the realistic US range from cheap overnight EV tariffs to the most expensive public ultra rapid charging.
| Tier | Default price | Basis |
|---|---|---|
| Home solar | $0.10 per kWh | Assumption. Not a tariff you pay — it is the solar feed-in credit given up by self-consuming rather than exporting. US net metering credits averaged roughly 3–6 c/kWh through 2026 and have been falling as daytime solar exports grow. |
| EV off peak | $0.13 per kWh | Assumption. Reflects dedicated overnight EV tariffs offered by some US retailers. Not all plans offer a rate this low. |
| Home off peak | $0.16 per kWh | Assumption. A typical off peak shoulder rate on a time-of-use plan. |
| Home standard rate | $0.18 per kWh | Assumption. A round figure for a flat residential tariff. Actual rates differ substantially between states and retailers. |
| Public AC | $0.32 per kWh | Assumption. Midpoint of the $0.40–$0.55 range this site quotes for public AC charging. |
| DC fast | $0.48 per kWh | Assumption. Within the $0.50–$0.75 range quoted for 50–150 kW public DC. |
| Ultra rapid DC | $0.56 per kWh | Assumption. Top of the range quoted for 250 kW+ public charging. |
How the solar figure is derived
Charging from your own rooftop solar does not produce an electricity bill, so it has no tariff to quote. What it does have is an opportunity cost: every kilowatt-hour you put into the car is one you did not export for a feed-in credit. That forgone credit is the honest price of solar charging, and it is what the $0.05 figure represents.
US net metering credits sat at roughly 3 to 6 cents per kilowatt-hour through 2026 and have been declining, because so much solar reaches the grid at midday that wholesale prices there are often near zero or negative. If your retailer pays more or less than 5 cents, enter your own feed-in rate as the solar price and every figure on the site will use it.
Two caveats worth stating plainly. This assumes the energy genuinely comes from your own generation, which means the car has to be plugged in during daylight — solar charging suits people who are home during the day or who have a charger at work, and does nothing for someone who only plugs in at night. It also ignores the cost of the solar system itself, on the reasoning that most people install solar for the household rather than for the car. If you are weighing up whether to install solar specifically to charge an EV, that is a payback calculation this site does not attempt.
These tiers are the site's own price ladder, not a published tariff schedule. They are used consistently everywhere so that comparisons between calculators are internally consistent. Enter your own rate to get a figure that means something for your plan.
State electricity rates
Selecting a state in the My EV panel replaces the Home standard rate tier above with that state's residential average. This matters more in the United States than in any other market this site covers: the spread runs from about 12.4 cents per kWh in Idaho to 52 cents in Hawaii, a difference of more than four to one. A single national figure is close to meaningless, which is why picking your state is the most useful thing you can do here after setting your vehicle.
Rates are residential averages in cents per kWh, from the US Energy Information Administration as compiled by Choose Energy, May 2026. The national average at that date was 18.4 cents. These are state-wide averages, not your utility's tariff: within a single state, rates differ between utilities, between rate plans, and between time-of-use periods. Your own bill is always the better number and you can enter it directly.
Public charging price ranges
Where a guide quotes a range rather than a single price, these are the ranges used.
| Charger type | Range used | Basis |
|---|---|---|
| Public AC charger | $0.22 – $0.40 per kWh | Assumption |
| DC fast charger (50 kW) | $0.34 – $0.50 per kWh | Assumption |
| DC rapid charger (150 kW) | $0.40 – $0.56 per kWh | Assumption |
| Ultra rapid charger (250 kW+) | $0.45 – $0.62 per kWh | Assumption |
Vehicle defaults
The vehicle list behind the My EV picker covers 71 electric cars sold in the United States, model years 2025 and 2026. Range is the EPA combined figure for that exact variant, taken from the EPA's own published data at fueleconomy.gov — the number on the car's window sticker, not the more optimistic WLTP figure used in Europe and Australia. Battery capacity and peak DC charging rate come from manufacturer specifications, since the EPA does not publish them. If your car is not listed, or your own numbers differ, every calculator accepts them directly and will use yours in preference.
| Figure | Default | Basis |
|---|---|---|
| Battery size | 100 kWh | Assumption. A round number, deliberately at the larger end so costs are not understated. Replaced by your vehicle's real capacity when you set a vehicle with My EV. |
| EV efficiency | 26 kWh per 100 miles | Assumption. A mid-range figure for a medium EV. Replaced by the vehicle's rated figure when you set a vehicle. |
| Everyday charge window | 10% to 80% | Assumption, reflecting common charging practice and the range over which DC charging is fastest. |
| Gas vehicle fuel use | 8.0 L per 100 miles | Assumption. A medium gas car. Change it to match the car you are actually comparing against. |
| Annual distance | 13,600 miles | Assumption. A round figure for an average private vehicle. The ABS Survey of Motor Vehicle Use is the obvious source for a real figure; this site does not currently cite it, so the number is not presented as sourced. |
| Gas price | $4.14 per gallon | National average (AAA national average, September 2026). Fuel prices move weekly and vary by city, so this one dates faster than any other default on the site. |
Vehicle specifications listed on the EV battery size list — battery capacity, EPA range, maximum DC charging power — combine the EPA's published range with manufacturer specifications for battery and charging rate. EPA range figures are laboratory test results and are still somewhat optimistic relative to real driving.
Charger types and power
Charging time calculations use these nominal power figures. Real charging power is rarely constant: it depends on the vehicle's own limit, the battery's state of charge and temperature, and whether the charger is shared with another car.
| Charger type | Power used | Typically found |
|---|---|---|
| Portable charger | 2.3 kW | Standard power outlet |
| AC wall charger | 7 kW | Home wall box (single phase) |
| 3-phase AC charger | 22 kW | Home, workplace or destination charger |
| DC fast charger | 50 kW | Public fast charging station |
| DC rapid charger | 150 kW | Public rapid charging station |
| Ultra rapid charger | 250 kW | Public ultra rapid station |
What the time calculations exclude
Charging time is calculated as energy divided by power, at constant power. Real DC charging follows a curve that tapers as the battery fills, so real charging sessions take longer than this site estimates, particularly above 80%. The site does not model the charging curve, battery temperature, preconditioning, or the vehicle's own maximum DC intake beyond the value stored for a selected vehicle.
Ownership costs
| Figure | Value used | Basis |
|---|---|---|
| EV servicing, per year | $400 (midpoint of $300 – $500) | Assumption. No source. Actual servicing cost varies by manufacturer, service interval and whether the vehicle is under a capped-price plan. |
| Gas servicing, per year | $500 – $800 | Assumption, used in guide comparisons only. |
| EV registration fee | $0 – $274 per year | Sourced. Set by each state. Forty-one states charge one; ten jurisdictions charge nothing. Flat annual amount, not per mile. The site uses your own state where one is set — see the state EV registration fees section below. |
| Gas road funding | Included in fuel excise | Sourced. Fuel excise is levied on gas and diesel at the point of sale, so gas running costs on this site already include a road funding component that EV costs do not. |
What running cost figures exclude
The running cost figures on this site cover energy and servicing only. They do not include purchase price, depreciation, financing, insurance, registration, tyres, or battery replacement. Depreciation and insurance are usually larger than fuel for a new vehicle, so a running cost comparison is not a total cost of ownership comparison and should not be read as one.
Range and range loss
Estimated range is battery capacity divided by efficiency. Driving conditions are applied as an adjustment to efficiency, not to the battery.
| Condition | Efficiency adjustment | Basis |
|---|---|---|
| City driving | −25% | Assumption. Lower speeds and regenerative braking. |
| Mixed driving | −12% | Assumption |
| Typical driving | Baseline | The vehicle's rated efficiency |
| Highway driving | +15% | Assumption. Based on typical US speed limits of 55 to 70 mph. |
| Fast highway | +25% | Assumption |
| Worst case | +50% | Assumption. Cold weather, highway speeds and cabin heating combined. |
These percentages are approximate and are not derived from a published dataset. Real variation depends on the vehicle, terrain, temperature, driving style and climate control use.
What the calculators do not account for
- Charging losses. Energy drawn from the wall is greater than energy stored in the battery, typically by a few per cent for DC and rather more for slow AC charging. The calculators treat energy added and energy paid for as the same quantity, so real costs are slightly higher than shown.
- Session and connection fees. Some public charging networks apply a per-session fee or an idle fee. Only the per-kWh price is modelled.
- Demand charges and supply charges. Home electricity bills include a daily supply charge that does not change with EV charging, and is therefore excluded.
- Solar. Charging from your own rooftop solar has a different cost basis again. Enter your own figure if this applies to you.
- Battery degradation. Usable capacity falls over a vehicle's life. All figures assume the battery's rated capacity.
- The charging curve. See the charging time note above.
State EV registration fees
Gasoline vehicles fund roads through federal and state fuel taxes collected at the pump. An electric car buys no gasoline, so most states charge an annual EV registration fee instead. These figures are used by the state EV cost calculator and in the running cost figures elsewhere on the site.
| Input | Value used | Basis |
|---|---|---|
| States charging a fee | 41 of 50, plus DC exempt | Sourced. Ten jurisdictions charge nothing: Alaska, Arizona, Connecticut, Florida, Maine, Massachusetts, Nevada, New Mexico, New York and the District of Columbia. |
| Typical fee | about $150 per year | Sourced. Median across the states that levy one. |
| Highest fee | $274 (Georgia) | Sourced. New Jersey and Michigan are close behind at $270 and $267. |
| Plug-in hybrid fees | usually about half | Sourced. PHEVs pay a reduced amount in most states because they also buy gasoline, and therefore pay some fuel tax. |
Per-state figures come from the Tax Foundation, July 2026, rounded to the dollar. Several states have legislated increases that phase in over the next few years, so a fee correct today may not be correct at your next renewal. Confirm with your state DMV before relying on it.
One structural point worth understanding. Unlike a per-mile road user charge, these fees are flat: the same amount whether you drive 5,000 miles a year or 25,000. That makes them proportionally hardest on low-mileage drivers, for whom the fee can exceed what they would have paid in gasoline tax, and negligible for high-mileage drivers. The calculator shows the fee as cents per mile at your own distance so the effect is visible rather than hidden in an annual total.
The federal tax credit
There isn't one any more. The $7,500 credit for new clean vehicles and the $4,000 used-vehicle credit both ended for vehicles acquired after 30 September 2025. This site therefore applies no federal purchase incentive, and no calculator here models one. State, local and utility programmes may still apply where you live, and the federal home charger credit may be available in eligible locations — both are worth checking separately, and neither is assumed anywhere in these figures.
Review schedule
Prices move. This page and the constants behind it are reviewed together, and the review date shown at the top of this page is the date of the last review of the figures themselves — not the date the page was last edited.
If a figure here looks wrong, or you have a source that would let an assumption become a sourced value, please get in touch. Corrections are welcome and will be credited on this page.