Electric Vehicle Range Calculator
Range Is a Multiplication, Not a Guess
An EV's window-sticker range figure assumes a fixed efficiency under test conditions, but real efficiency shifts with speed, temperature, terrain, and how the current charge level compares to a full battery. Instead of relying on a single published number, this calculator multiplies actual usable energy by a chosen efficiency figure, so the estimate reflects the battery's real state of charge and whatever efficiency you observe or expect to drive at.
The Formula
Imperial: Range = Usable Energy × Efficiency (miles/kWh)
Metric: Range = (Usable Energy ÷ Efficiency (kWh/100km)) × 100
Efficiency can come from a manufacturer's EPA/WLTP rating, an onboard trip computer average, or a personal average logged over recent driving.
Where This Matters
- Trip planning — entering the actual current charge percentage, rather than assuming a full battery, gives a realistic range before the next charging stop is needed.
- Seasonal adjustment — cold weather commonly reduces real-world EV efficiency; lowering the efficiency input reflects that drop without needing a separate formula.
- Comparing driving styles — highway speeds and aggressive acceleration both increase energy use per mile; entering a lower efficiency figure models a more demanding drive.
- Buying decisions — comparing two vehicles' battery capacity and efficiency side by side shows which one actually delivers more usable range for a given driving pattern.
Range from a 75 kWh Battery at Full Charge
| Efficiency | Estimated Range |
|---|---|
| 2.5 mi/kWh | 187.5 miles |
| 3.0 mi/kWh | 225.0 miles |
| 3.5 mi/kWh | 262.5 miles |
| 4.0 mi/kWh | 300.0 miles |
| 4.5 mi/kWh | 337.5 miles |
Computed directly from Range = Usable Energy × Efficiency at a fixed 75 kWh usable battery capacity. Published EV efficiency ratings commonly fall within this range depending on vehicle size and conditions.
How to Use This Calculator
- Select Imperial (miles/kWh) or Metric (kWh/100km) units.
- Enter the battery's total capacity in kWh.
- Enter the efficiency figure for the selected unit system.
- Enter the current charge percentage (defaults to 100% for a full battery).
- Select Calculate to see estimated remaining range.
Related Calculations
Once you know how much energy a trip will use, the EV Charging Cost Calculator estimates what refilling that energy will cost.