EV Range Calculator
Estimate how far your electric car can drive on its current charge. Enter your usable battery capacity, state of charge, energy consumption and the reserve you want to keep, and get the remaining range in km or miles.
Estimate How Far Your EV Can Drive on the Current Charge
EV Range Formula
Where:
- \(C\) — usable battery capacity of the EV (kWh)
- \(SoC\) — current state of charge shown on the dashboard (%)
- \(R\) — reserve charge you want to keep in the battery (%)
- \(E_u\) — usable energy until the reserve level (kWh)
- \(E_c\) — average energy consumption (kWh/km or kWh/mi)
- \(d\) — estimated remaining range (km or mi, matching the consumption unit)
The first line works out how much energy is actually available between your current charge and the reserve you never want to dip below; the second line divides that energy by your car's real-world consumption to estimate the distance you can still drive.
EV Range – Calculation Example
Example: an EV with a usable battery of 60 kWh is charged to 80%. The driver averages 0.18 kWh/km and wants to arrive at a charger with at least 10% left.
\[ E_u = \frac{60 \times (80 - 10)}{100} = \frac{60 \times 70}{100} = 42 \text{ kWh} \]
\[ d = \frac{42}{0.18} \approx 233 \text{ km} \]
Result: the estimated remaining range is about 233 km (roughly 145 mi), with 42 kWh usable before the 10% reserve is reached.
How to Use the Calculator
- Enter the Usable Battery Capacity in kWh. Check your car's manual or spec sheet — this is the usable figure, not the gross figure (e.g. a car advertised with a 64 kWh gross battery may have only ~60 kWh usable).
- Enter the Current Charge percentage exactly as shown on your dashboard or app.
- Enter your Energy Consumption and pick the right Consumption unit — kWh/km or kWh/mi. Use your car's trip computer average rather than the official rating for the most realistic result.
- Set the Reserve Charge — the buffer you want to keep for heating, detours, headwinds or a busy charger. 10% is a sensible default; many drivers use 15–20% in winter or on long trips.
- Read the Estimated Remaining Range and the Usable Energy Until Reserve in the results.
What the Calculation Means
Every electric car displays some form of remaining range, but that estimate is usually based on a fixed (often optimistic) consumption value. This calculator replaces that guess with your own measured consumption, so the result reflects how you actually drive rather than a laboratory test cycle.
The reserve charge is what turns a theoretical number into a trip-planning number. Running an EV down to 0% is bad for the battery, stressful, and leaves nothing for an unexpected detour or an occupied charging station. By subtracting the reserve up front, the calculator tells you the distance you can cover while still arriving above your safety buffer — the figure you should actually plan routes and charging stops around.
The distance unit always follows your consumption unit. If you enter consumption in kWh/mi, the range comes out in miles; if you enter kWh/km, it comes out in kilometers. For reference, \(0.18\ \text{kWh/km} \approx 0.29\ \text{kWh/mi}\), and typical real-world values range from about 0.13 kWh/km for very efficient compact EVs to 0.25 kWh/km or more for large SUVs and pickups, especially at highway speeds or in cold weather.
Assumptions, Limitations and Practical Tips
The calculator assumes consumption stays roughly constant over the remaining charge, which is a simplification. Real range is affected by:
- Temperature: below about 5 °C (41 °F), cabin heating and battery conditioning can increase consumption by 20–40%.
- Speed: aerodynamic drag grows with the square of speed; driving 130 km/h instead of 100 km/h can cut range by 25% or more.
- Terrain and wind: a long climb or a headwind drains the battery noticeably faster; regenerative braking only partially recovers the energy on the way down.
- Load and tires: heavy luggage, roof boxes, winter tires and low tire pressure all raise consumption.
For long trips, plan with a consumption value about 15–25% above your fair-weather average, and treat the calculator's output as a best-case estimate rather than a guarantee. If your state of charge is already at or below the reserve, the calculator will tell you the battery is at your buffer — time to charge.
One more practical note: the usable energy figure (\(E_u\)) is handy on its own. Dividing it by your charger's power tells you roughly how long a top-up to the next stop will take, and multiplying it by your electricity price gives the cost of the energy you'll use — useful if you're splitting travel costs with passengers on a shared road trip.
Frequently Asked Questions
How do I calculate EV range by hand?
Multiply the usable battery capacity by the percentage of charge you can actually use, then divide by your consumption. For example, with a 60 kWh battery at 80% charge and a 10% reserve: \(60 \times (80-10)/100 = 42\) kWh available. Divide by consumption, say 0.18 kWh/km, to get \(42 / 0.18 \approx 233\) km. The whole formula fits on one line: \(d = C(SoC - R) / (100 \, E_c)\).
What is a good real-world energy consumption for an EV?
Efficient compact EVs typically use 0.13–0.17 kWh/km (about 4 miles per kWh), while large SUVs and pickups can exceed 0.25 kWh/km, especially at highway speed or in cold weather. If your dashboard shows efficiency in mi/kWh, invert it: 4 mi/kWh equals \(1/4 = 0.25\) kWh/mi. Always use your trip computer's recent average rather than the official rating, which tends to be optimistic.
How do I convert between kWh/km, kWh/mi and mi/kWh?
To convert kWh/km to kWh/mi, multiply by 1.609: \(0.18\ \text{kWh/km} \approx 0.29\ \text{kWh/mi}\). If your car displays miles per kWh, take the reciprocal: 3.5 mi/kWh equals about 0.286 kWh/mi. To convert the final range figure, 1 mile is 1.609 km, so 233 km is roughly 145 miles.
Why is my calculated range lower than what the dashboard shows?
Most built-in range estimates use a fixed, laboratory-derived consumption value, often based on mild-weather test cycles. Real driving involves hills, wind, cabin heating and highway speeds that raise consumption well above the test figure. When you enter your actual trip-computer average instead, the result is usually 15–30% shorter — and far more trustworthy for planning charging stops.
What reserve charge should I keep when planning a trip?
10% is a common default buffer; many drivers use 15–20% in winter or on unfamiliar routes. The reserve covers detours, a broken or occupied charger, and the fact that the last few percent of a battery may deliver reduced power. Note that the buffer here is a percentage of the battery, so 10% of an 80 kWh pack means 8 kWh — about 40–60 km of extra safety margin in most cars.
How much does cold weather reduce EV range?
Below about 5 °C (41 °F), expect 20–40% higher consumption due to cabin heating and battery conditioning. Driving 130 km/h instead of 100 km/h can cut range by another 25% because aerodynamic drag grows with the square of speed. For winter road trips, enter a consumption value 25% above your fair-weather average or your estimate may be dangerously optimistic.
Can I use this calculator to estimate charging time or cost?
Yes, indirectly. The usable energy result \(E_u\) in kWh is the energy you plan to consume. Divide it by your charger's power to estimate top-up time — for example, 42 kWh at 100 kW takes about 25 minutes — and multiply it by your electricity price (per kWh) to get the cost of that leg of the trip, useful for splitting travel expenses. Note that charging slows down above roughly 80% state of charge.