How does the EV range calculator work?
The calculator converts your usable battery charge into miles using your vehicle's efficiency, after setting aside any reserve you'd rather not drive below.
Enter battery & charge
Set your battery capacity in kWh and your current charge percentage.
Enter your efficiency
Use your vehicle's real-world miles per kWh, found on your dashboard or owner's manual.
View your estimated range
See how far you can drive now, plus your full-charge range for comparison.
Why a reserve matters
Planning to arrive at exactly 0% leaves no margin for a detour, unexpected traffic, or a charging stop that turns out to be occupied or out of order. This calculator sets aside a reserve percentage — 10% by default — before converting the rest of your charge into range, so the estimate reflects charge you'd actually be comfortable using rather than every last kilowatt-hour in the battery.
Usable charge is your current charge minus your reserve; adjusted efficiency applies your weather or driving-condition adjustment.
Worked example: checking a trip against a cold-weather charge
An 82 kWh EV at 62% charge, cold weather and highway driving
Suppose your EV has an 82 kWh battery, you're at 62% charge, and your normal efficiency is 3.2 miles per kWh. You're about to drive 95 miles on the highway on a cold day, and want to keep a 10% reserve. Cold temperatures and sustained highway speed together are cutting your real-world efficiency by roughly 25% today.
- Usable charge: 62% − 10% reserve = 52%.
- Usable energy: 82 kWh × 0.52 = 42.64 kWh.
- Adjusted efficiency: 3.2 mi/kWh × (1 − 0.25) = 2.4 mi/kWh.
- Estimated range: 42.64 kWh × 2.4 mi/kWh ≈ 102 miles.
With an estimated 102 miles available above your reserve, and a 95-mile trip ahead, you'd arrive with roughly a 7-mile cushion on top of your reserve — comfortable, but tight enough that a charging stop partway would be a reasonable precaution rather than cutting it close on a cold day.
Result: about 102 miles available now, versus a 236-mile range if the same battery were charged to 100% in normal conditions.
What changes your real-world range
Temperature has one of the biggest effects — cold weather increases cabin heating demand and can temporarily reduce battery performance, often cutting range by 10–40% depending on how cold it is and how the cabin is heated. Driving speed matters too: sustained highway speeds increase aerodynamic drag, which is why highway efficiency is often lower than city efficiency, where regenerative braking during stop-and-go driving helps recover energy. Payload, tire pressure, elevation gain, and accessory use (like air conditioning or towing) can each shift efficiency by a smaller but still noticeable amount.
How to find your real-world efficiency
Most EVs display a lifetime or trip efficiency figure on the dashboard in miles per kWh or a similar unit — this is generally more accurate for planning than the EPA-rated figure, which represents a standardized test cycle rather than your actual driving. If your typical driving is a mix of city and highway, use your dashboard's overall average; if you're planning a trip that's mostly one or the other, consider adjusting the efficiency figure or using the range-adjustment field to reflect that specific driving style.
Common ways to use this calculator
Compare your estimated range against a specific trip distance before you leave.
See how far you can go before you'd want to stop, keeping a comfortable reserve.
Estimate how much cold weather is likely to cut your usual range.
See how much extra range charging to 90% or 100% adds versus your usual charge level.
Privacy and appropriate use
Your inputs are processed directly in your browser and are not sent to a database. The result is a planning estimate; always keep a safety margin on unfamiliar routes, and rely on your vehicle's live range estimate once you're driving.