EV range from battery and efficiency calculator
With 72 kWh of usable battery and 180 Wh per mile, an electric car travels 400 miles. Enter the energy you can really use, say whether consumption is per mile or per kilometer, and read both distances. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Usable battery kwh
- 72
- Consumption wh per distance
- 180
- Distance unit
- Mile
- Usable energy wh
- 72,000
- Estimated range
- 400
- Estimated range miles
- 400
- Estimated range kilometers
- 643.7376
This EV range from battery and efficiency calculator estimates how far an electric vehicle can travel when you know its usable battery capacity and its energy consumption. Enter usable capacity in kilowatt-hours, enter consumption in watt-hours per mile or watt-hours per kilometer, and select the matching distance unit. The result includes the primary range in that unit plus converted totals in both miles and kilometers. It uses a transparent, deterministic formula without live vehicle data, weather assumptions, network calls, or hidden adjustments, making it useful for quick planning, comparisons, and repeatable software calculations.
Enter usable battery energy, not merely the advertised pack size
Begin with the energy that can actually be used for driving, expressed in kilowatt-hours. An advertised gross battery size may include upper and lower buffers that protect battery health, so it can be larger than usable capacity. If a manufacturer publishes both figures, choose the usable figure for this calculation.
If you only know gross capacity, the result should be treated as an optimistic ceiling unless you first subtract the reserved buffer. The calculator converts usable kilowatt-hours to watt-hours by multiplying by one thousand. That conversion puts battery energy in the same unit as the consumption input.
Capacity must be finite and greater than zero; missing, zero, negative, or nonnumeric values are rejected rather than turned into a misleading distance. A partial charge can also be represented: multiply the full usable capacity by the starting state-of-charge fraction before entering it. For example, a vehicle with sixty usable kilowatt-hours at an eighty percent starting charge has forty-eight kilowatt-hours available.
This approach also works for an energy budget deliberately held in reserve, provided you subtract that reserve before supplying the capacity. Keeping the input tied to genuinely available energy makes comparisons more useful and avoids implying that protected battery buffers are available on the road.
Match watt-hour consumption to the correct distance unit
Next enter the vehicle's consumption as watt-hours per mile or watt-hours per kilometer and select exactly which distance unit that number describes. These rates are not interchangeable: 180 Wh per kilometer represents substantially greater energy use than 180 Wh per mile. Dashboard trip summaries, independent road tests, and vehicle specifications may use either convention, so read the label rather than assuming a unit.
The core formula is available watt-hours divided by watt-hours consumed per distance unit. The units cancel cleanly, leaving miles when consumption is Wh per mile or kilometers when consumption is Wh per kilometer. Consumption must be a finite number greater than zero because zero would require division by zero and a negative energy rate has no physical meaning for this estimate.
The calculator reports the result in the selected primary unit and also converts it into the other distance unit using the exact international relationship of one mile to 1.609344 kilometers. Use an efficiency figure representative of the trip you care about; a mixed urban rating may not describe sustained motorway driving, winter heating, towing, steep climbing, or strong headwinds.
Interpret the estimate as an energy-based planning baseline
The output is an arithmetic range estimate, not a promise that a vehicle will reach the displayed distance under every condition. A sensible planning workflow calculates a baseline from a representative consumption rate, then applies a safety margin appropriate to the route and charging options. You might compare a mild-weather rate with a conservative winter rate, or reserve part of the battery for reaching an alternate charger.
No live telemetry, route geometry, charger status, or weather data is fetched, and no probabilistic model is used. For route-specific decisions, combine this result with current conditions and charger availability. For vehicle comparisons, keep consumption measurements on the same test basis so differences reflect the vehicles rather than incompatible testing conditions.
What you can do with it
Pre-trip energy check
Turn available battery energy and a realistic trip consumption rate into a baseline distance before selecting charging stops.
Compare EV efficiency
Use the same usable capacity with different Wh per mile or Wh per kilometer figures to see how consumption affects range.
FAQ
What formula does the calculator use?
It multiplies usable battery kWh by 1,000 to obtain Wh, then divides that energy by consumption in Wh per selected distance unit.
Should I enter gross or usable battery capacity?
Enter usable capacity. Gross pack capacity can include protected buffers that are unavailable for ordinary driving.
Can consumption be entered in Wh per mile and Wh per kilometer?
Yes. Select mile or kilometer to identify the distance unit represented by your watt-hour consumption value.
How do I estimate range from a partial charge?
Multiply your full usable capacity by the starting charge as a fraction, then enter that figure as the capacity. The same trick works for a reserve you want to keep: subtract it first, so the range only counts energy you will really spend.
What if I mix up Wh per mile and Wh per kilometer?
The result will be far off, because 180 Wh per kilometer means much more energy use than 180 Wh per mile. Dashboards, road tests and spec sheets use either convention, so check the label before choosing the unit.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/travel/ev-range-from-battery \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"usable_battery_kwh":72,"consumption_wh_per_distance":180,"distance_unit":"mile"}'const res = await fetch("https://api.kit.forhosting.com/travel/ev-range-from-battery", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"usable_battery_kwh": 72,
"consumption_wh_per_distance": 180,
"distance_unit": "mile"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/travel/ev-range-from-battery",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"usable_battery_kwh": 72,
"consumption_wh_per_distance": 180,
"distance_unit": "mile"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/travel/ev-range-from-battery", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"usable_battery_kwh":72,"consumption_wh_per_distance":180,"distance_unit":"mile"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"usable_battery_kwh":72,"consumption_wh_per_distance":180,"distance_unit":"mile"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/travel/ev-range-from-battery", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"usable_battery_kwh": 72,
"consumption_wh_per_distance": 180,
"distance_unit": "mile"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "travel.ev_range_from_battery",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Interpret the estimate as an energy-based planning baseline
Real consumption changes with speed, temperature, cabin heating or cooling, elevation, wind, tire pressure, payload, traffic, and driving style. The response echoes the normalized inputs, shows usable energy in watt-hours, provides estimated range in the requested unit, and includes both mile and kilometer equivalents. This makes the result easy to audit in a spreadsheet, fleet workflow, trip-planning prototype, or automated test. The browser version is useful for one-off checks, while an API request costs $0.002 when the same deterministic calculation needs to run inside software.
Integration use cases
Build repeatable range fixtures
Generate deterministic mile and kilometer outputs for fleet tools, calculators, spreadsheets, and automated software tests.
Technical questions
Why might real driving range be lower?
Speed, cold weather, heating, hills, wind, payload, tires, and driving style can increase consumption beyond the value entered.
How much does an API calculation cost?
Each successful API request costs $0.002. You can also run the calculator interactively in the browser.