EV range calculator for real-world speed and weather
This EV range calculator estimates how far an electric car will go on the charge it has now, in kilometres or miles. Official range figures come from mixed test cycles in mild weather; on a cold motorway trip the real number can be far lower. The calculator starts from your battery and your car’s energy use, then adjusts for speed, temperature with or without heating or air-conditioning, extra load and anything else you add.
Each adjustment is shown separately, so you can see whether the cold or the speed is costing you most, and a table shows the range at other steady speeds. Every default can be changed, and nothing leaves your browser.
How to estimate your EV range
- Choose km or miles.
- Enter the Usable battery capacity, the Charge now and how much you want to Keep in reserve.
- Enter a Baseline energy use from your trip computer for mild weather and the steady speed it was measured at.
- Enter the Cruising speed, Outside temperature, whether heating or air-con is on, any Extra load and any other extra use in per cent.
- Read the estimate, the bars and the speed table. Open Car details to match the model to your car.
EV Range Calculator features
Speed adjustment
A road-load model: rolling resistance grows with weight, air drag with the square of speed.
Temperature adjustment
Interpolated from AAA’s measured range losses at −6.7 °C, 23.9 °C and 35 °C, with and without climate control.
Load and extras
Extra passengers and luggage, plus a free percentage for roof boxes, rain or hills.
Factor-by-factor bars
See the range after each adjustment, from your baseline to the estimate.
Any units
kWh/100 km, km/kWh, mi/kWh, Wh/mi or kWh/100 mi; °C or °F; km/h or mph.
How the EV range estimate works
Range = usable kWh × (charge now − reserve) ÷ 100 ÷ energy use per km. The energy use is your baseline multiplied by a speed-and-load factor, a temperature factor and your “other” percentage.
The speed factor compares the energy per metre at the two speeds: (Crr × mass × g + ½ × air density × CdA × v²) ÷ drivetrain efficiency + other electrical load ÷ v. Rolling resistance is roughly constant, but drag rises with the square of speed, so the jump from 90 to 110 km/h costs more than the jump from 50 to 70. The default car values (1,900 kg, CdA 0.62 m², Crr 0.009, 0.3 kW, 85% efficiency) are typical of a mid-size electric SUV, not any particular model.
Worked example: 60 kWh from 90% down to 10% leaves 48 kWh. At 16 kWh/100 km that is 300 km at a steady 90 km/h in mild weather. At 110 km/h with 100 kg extra and the heater on at 10 °C the model gives about 188 km — speed costs about 22%, the cold with the heater on about 19%.
How much does cold weather reduce EV range?
In February 2019 AAA tested five electric cars on a dynamometer under the SAE J1634 procedure and compared the range with a 75 °F (23.9 °C) baseline:
| Outside temperature | Climate control off | Heater or AC on |
|---|---|---|
| 20 °F (−6.7 °C) | −12% | −41% |
| 75 °F (23.9 °C) | 0% (baseline) | 0% (baseline) |
| 95 °F (35 °C) | −4% | −17% |
Tips for more range
- Precondition the cabin and battery while plugged in, and use seat and steering-wheel heaters, which use less energy than heating the air.
- Slow down on the motorway: with the default car values, 130 km/h gives over a third less range than 90 km/h.
- Check tyre pressures and remove roof boxes when not needed.
- Plan a long trip’s charging stops with the EV road trip planner, each stop’s time with the EV charging time calculator and their cost with the EV charging cost calculator.
EV Range Calculator FAQ
How do I calculate my EV’s range?
Divide the usable battery energy you have (kWh × charge %) by the car’s energy use per km or mile. The EV range calculator above then adjusts for speed, temperature and load.
How does speed affect EV range?
Air drag grows with the square of speed, so range falls quickly above about 100 km/h (60 mph). Enter different cruising speeds or look at the speed table to see the effect for your car.
How much range does an EV lose in winter?
In AAA’s 2019 tests, range fell 12% at −6.7 °C without heating and 41% with the heater on. Short trips in the cold lose the most; a preconditioned car on a long trip loses less.
Does air-conditioning reduce EV range?
Yes, but usually less than heating. At 35 °C AAA measured a 17% drop with the air-conditioning on and 4% with it off.
Why is my range lower than the official WLTP or EPA figure?
Test cycles include a lot of slow driving in mild conditions. Motorway speeds, cold weather, heating and extra weight all raise energy use.
Is the estimate exact?
No. It is a model with average values: wind, hills, tyres, battery age and driving style all change real range. Keep a margin.